% by Neng-Fa Zhou, Jan. 2012

maxflow(M,Source,Sink):-
    N is M^length,
    new_array(X,[N,N]),
    foreach(I in 1..N, J in 1..N, 
        X[I,J] :: 0..M[I,J]
    ),
    term_variables(X,Vars),
    foreach(I in 1..N, 
        (I\==Source,I\==Sink->
             sum([X[J,I] : J in 1..N]) $= 
             sum([X[I,J] : J in 1..N]) 
        ;
             true
        )
    ),
    Total $= sum([X[Source,I] : I in 1..N]),
    Total $= sum([X[I,Sink] : I in 1..N]),
    ip_solve([max(Total)],[Total|Vars]),
    writeln(Total).

go :-
        A= []([](0,0,0,7,8,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,4,0,0,0,0,0,0,6,8,0,0,0,5,0,0,0,0,0,4,0,0,0,0,0,0,0,0,0,0,0,0,4,0,0,5,0),[](0,9,5,0,0,0,0,0,8,1,0,0,0,0,9,4,5,0,0,0,6,4,8,2,0,3,7,0,0,0,2,0,0,0,6,4,0,0,5,1,0,0,0,0,0,0,0,0,8,0,0,4,0,0,0,5,0,0,0,0),[](0,8,0,0,0,4,0,0,0,0,0,0,0,8,5,1,1,0,2,0,0,5,0,0,0,0,0,0,7,0,5,0,0,0,0,8,0,0,4,0,5,3,0,0,0,0,0,0,0,0,0,0,8,0,0,0,1,0,6,0),[](0,0,0,9,0,0,0,0,1,4,7,4,0,7,0,0,4,0,8,0,0,5,0,0,2,0,0,0,0,4,3,0,0,0,0,2,0,0,0,7,1,5,9,0,0,0,0,0,6,0,0,0,3,0,0,4,8,1,0,8),[](0,0,0,3,9,0,0,7,7,0,0,0,0,0,0,0,0,0,0,7,0,0,0,0,0,0,0,0,0,0,0,8,0,4,2,0,0,8,8,1,9,9,4,0,0,9,1,0,0,0,0,0,0,0,0,7,0,0,0,0),[](8,0,3,0,0,0,0,0,8,7,0,7,0,0,7,0,0,0,9,0,0,0,0,0,5,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,6,0,0,0,0,0,0,6,7,0,4,0,0,2,4,0,0),[](3,9,0,0,9,0,0,4,0,0,9,2,0,0,0,0,0,0,0,0,0,0,0,0,9,0,7,0,6,1,7,0,6,0,8,1,0,0,0,0,3,0,0,0,0,8,0,0,0,7,7,2,0,7,0,9,0,0,0,0),[](0,0,8,6,0,0,0,0,0,0,0,6,0,0,0,0,0,2,7,0,3,1,0,9,4,9,3,0,2,0,0,0,0,8,0,0,0,2,9,0,0,0,0,0,0,0,1,9,0,0,0,0,0,0,0,7,5,0,0,0),[](0,0,0,5,7,0,4,7,0,0,5,0,0,8,4,0,0,4,0,0,0,0,0,0,0,4,0,0,0,0,5,0,5,0,0,0,0,5,0,0,0,2,0,0,0,0,5,0,0,0,0,0,0,0,6,5,0,0,0,3),[](0,0,0,6,0,0,0,0,8,0,0,0,0,0,0,0,0,0,0,0,0,2,1,0,0,0,0,0,0,0,0,0,3,0,0,0,6,0,0,7,9,0,0,0,0,3,0,1,0,0,0,0,0,0,5,0,0,0,0,0),[](8,0,0,0,0,0,6,0,0,0,4,0,7,7,3,0,0,9,0,0,0,0,0,3,0,0,8,0,0,4,0,7,0,0,0,3,0,0,0,0,0,0,6,3,0,0,0,0,2,0,0,0,0,0,0,0,0,7,0,0),[](0,0,3,5,3,0,0,0,2,0,0,0,7,0,0,0,0,0,0,0,4,5,0,0,9,0,0,0,0,0,0,2,6,0,0,0,0,0,9,0,0,0,0,0,0,0,3,0,0,0,0,0,0,2,6,0,0,8,0,0),[](0,0,0,4,0,0,0,5,7,6,0,6,0,0,0,0,0,0,0,0,7,0,0,0,2,0,4,0,1,0,0,8,7,0,0,0,0,0,0,0,0,0,0,0,7,0,0,0,5,0,0,0,5,0,0,0,8,9,5,9),[](0,0,0,0,6,5,0,0,0,0,8,0,1,0,4,6,0,0,0,5,0,0,0,0,8,0,0,0,0,1,0,5,0,0,0,0,0,6,0,0,0,0,0,0,1,0,4,2,0,4,0,0,0,2,0,0,3,0,8,0),[](0,9,2,0,0,0,0,0,9,6,0,0,3,0,0,4,0,0,0,0,3,0,0,5,1,0,0,0,0,3,0,0,0,0,9,0,4,0,0,9,0,0,0,0,0,0,0,0,0,0,0,0,6,0,0,0,0,0,5,4),[](0,7,0,0,0,1,9,1,0,4,0,4,0,0,0,0,0,7,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,9,2,6,8,0,0,0,0,1,0,0,0,0,0,0,9,7,7,9,0,0,0,6,3,4,0,5),[](0,0,0,7,0,0,6,9,0,0,2,0,6,7,0,0,0,0,3,2,0,2,0,0,0,8,0,0,0,0,8,0,0,7,0,0,0,6,1,0,8,6,0,0,0,3,0,0,0,0,0,0,2,0,0,0,0,9,0,0),[](6,8,0,0,0,0,0,3,0,0,0,0,0,0,5,1,2,2,2,2,0,0,9,0,4,0,2,0,5,8,0,0,0,0,0,1,0,0,5,0,0,0,0,8,0,0,0,0,0,5,0,0,0,3,5,5,0,0,0,0),[](2,0,8,7,0,0,0,0,0,5,0,0,0,0,0,0,7,0,0,0,0,0,9,0,0,0,0,0,0,0,0,0,0,0,0,2,0,0,8,6,0,9,9,0,0,6,0,6,6,0,0,1,3,9,0,0,0,9,0,0),[](3,7,0,0,0,0,0,0,0,0,0,8,0,9,0,0,0,0,0,0,8,5,0,0,0,0,0,0,0,0,0,0,0,0,5,0,0,0,1,4,0,0,0,0,0,0,0,7,6,8,0,5,2,9,0,0,0,0,0,0),[](0,0,0,7,0,0,0,0,0,6,0,7,3,0,1,8,7,0,0,0,0,6,0,0,0,0,0,0,0,7,0,0,0,0,2,0,0,0,0,0,0,6,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0),[](0,0,0,0,0,0,0,0,8,3,3,3,3,0,0,3,5,2,9,9,0,0,0,5,1,3,1,0,0,0,4,1,4,7,5,0,0,0,0,8,0,1,8,5,0,0,0,0,0,0,0,0,8,0,1,2,8,0,0,3),[](0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7,0,0,0,0,0,0,0,3,0,0,0,8,0,3,2,1,0,0,0,0,0,0,0,0,0,0,3,8,0,0,0,0,0,0,0,3,9,2,0,0,1,0,6,0),[](0,0,0,0,0,4,0,9,0,4,8,6,8,6,0,2,0,1,1,0,0,0,0,0,0,0,6,0,0,0,0,1,0,0,0,0,8,0,4,4,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,1,0),[](0,0,6,9,0,0,9,2,0,5,0,0,6,4,0,5,5,0,6,0,0,0,0,8,0,5,0,0,0,0,0,0,0,0,0,0,0,8,0,0,0,0,0,6,0,0,1,8,0,0,0,0,0,0,8,0,0,0,0,5),[](8,3,0,0,0,0,0,0,0,4,2,5,0,5,9,4,0,0,0,4,7,3,1,0,0,0,0,5,0,0,1,0,0,0,0,0,0,0,9,6,0,0,0,0,0,0,2,0,7,1,2,6,0,0,8,1,0,0,0,0),[](1,4,3,4,0,0,0,0,1,8,0,3,5,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,4,0,9,4,0,0,0,0,0,0,0,0,0,8,0,0,0,0,9,0,6,4,0,0,0,0,0,0),[](0,0,0,0,8,5,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,4,6,6,7,0,0,7,0,0,0,0,0,0,9,6,0,0,0,4,0,0,7,0,5,0,0,0,0,0,0,0,0,2,0,8,0,0),[](0,0,0,7,0,7,9,0,0,0,0,6,0,0,0,0,0,0,0,0,3,6,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,0,0,9,0,5,0,0,0,6,0,0,2,4,8,0,0,0,0,0,0,0,0,0),[](0,0,1,0,0,0,0,0,0,0,0,0,6,0,0,0,0,0,0,0,9,0,0,3,0,0,2,2,9,2,6,3,2,0,4,0,0,0,0,6,4,0,1,0,0,0,7,0,2,4,0,0,4,0,0,0,7,0,0,9),[](4,0,0,0,8,0,0,0,0,0,0,0,0,0,0,0,9,2,0,0,3,0,7,6,0,0,0,0,0,0,8,0,0,8,0,6,0,0,0,2,0,0,0,0,0,0,0,8,0,0,0,0,0,9,4,7,3,5,6,8),[](4,9,0,0,0,0,2,0,1,4,9,0,0,8,0,0,0,5,0,0,0,0,0,1,4,0,8,0,0,0,0,0,0,0,4,0,0,0,0,0,1,0,2,4,0,7,5,0,0,5,0,0,0,2,6,4,0,0,9,0),[](8,0,2,0,0,0,0,9,0,0,0,0,6,0,0,0,0,9,0,0,2,0,0,0,0,3,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,6,2,0,7,8,3,0,1,0,0,0,0,2,0,0),[](5,0,0,9,1,3,3,4,0,0,0,0,8,0,0,0,0,0,4,0,9,0,0,0,0,7,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,8,0,0,6,0,2,0,0,9,9),[](9,0,3,0,0,0,0,0,0,0,3,0,2,0,9,0,6,4,1,0,0,0,2,8,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,9,0,0,0,0,0,1,1,9,0,5,0,0,0,0,4,4),[](4,5,8,2,1,5,0,0,0,0,4,0,0,3,0,8,0,0,6,0,0,2,0,0,0,0,0,0,0,0,5,9,0,0,0,0,0,3,2,0,0,0,0,0,0,5,7,6,8,0,0,0,7,0,0,0,3,5,0,0),[](0,0,0,0,0,1,7,1,4,0,0,0,0,2,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,4,0,0,3,0,0,0,0,6,0,0,0,5,0,0,6,1,0,0,0,0,0,0,0,0,0,0,0,0,0,7),[](0,0,1,0,2,0,5,0,0,0,6,6,0,0,0,0,0,0,0,0,0,0,0,4,0,3,5,0,0,0,0,0,0,0,0,0,5,6,4,0,6,7,8,0,0,0,0,0,0,0,0,1,1,0,0,4,7,0,0,0),[](0,0,0,0,0,0,7,0,0,2,9,0,0,0,0,0,0,0,0,0,0,0,0,1,0,2,0,0,1,8,0,0,0,0,8,2,0,0,0,0,0,5,3,1,0,0,0,6,0,6,0,0,0,0,0,3,0,0,0,2),[](0,0,0,0,0,0,0,0,0,2,0,0,0,0,1,0,2,7,0,4,2,0,0,0,0,0,0,0,0,0,3,7,0,0,1,7,4,0,3,0,0,0,0,0,0,0,0,0,0,1,5,2,0,8,0,7,0,3,7,9),[](4,0,0,0,0,0,0,0,0,0,8,0,0,0,0,7,0,0,0,0,0,9,2,9,0,0,0,0,0,0,0,1,0,2,0,0,6,0,0,0,0,0,5,0,3,0,0,0,0,0,8,7,0,9,8,0,0,0,0,0),[](7,9,0,0,0,0,4,0,0,0,0,0,0,0,0,0,0,0,6,0,0,0,0,5,6,0,1,0,0,4,0,8,0,1,0,0,4,0,0,7,3,0,5,0,0,0,9,0,0,0,5,4,0,0,7,0,0,0,0,0),[](5,5,4,0,0,0,0,0,0,0,0,0,9,0,0,0,0,0,3,7,0,0,0,0,9,7,7,1,0,0,0,8,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,7,2,0,0,1,4,4,0,9,0,0,0,9),[](3,0,0,0,2,0,0,0,0,0,2,0,0,0,6,0,0,0,0,0,0,2,7,5,0,8,0,9,0,0,0,9,0,0,4,0,1,6,0,7,0,0,0,5,3,0,6,0,0,4,2,0,0,6,0,0,0,0,0,0),[](0,0,0,0,0,0,4,0,0,1,3,0,0,0,0,0,0,1,0,7,8,2,0,0,0,0,0,0,0,7,0,8,0,0,0,1,0,0,4,3,0,0,0,0,2,0,0,4,0,0,2,0,3,1,0,0,0,0,0,5),[](0,0,0,6,0,0,2,0,0,0,0,0,0,0,3,4,0,0,0,0,0,7,9,6,2,0,1,0,3,3,0,2,0,0,6,4,0,0,0,0,0,6,5,0,2,0,5,0,0,0,7,1,0,0,4,0,0,0,0,0),[](0,0,0,3,6,4,0,8,0,1,6,0,0,1,0,7,0,0,0,0,0,0,9,0,0,0,0,0,2,2,0,0,0,0,0,0,0,0,4,3,0,0,3,0,0,1,1,4,0,8,5,0,0,0,0,0,0,0,4,0),[](0,0,0,0,7,0,4,0,0,8,0,6,2,0,0,0,2,0,3,0,1,6,0,0,0,0,0,0,0,0,5,6,0,7,0,0,8,0,0,3,0,6,0,0,0,0,0,0,7,0,0,4,0,0,0,0,0,0,7,0),[](0,0,0,0,5,6,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,4,4,8,6,3,7,0,0,0,0,1,0,0,0,8,7,1,0,0,0,8,0,0,2,0,0,0,0,1,0,5,1,0,0,5,0),[](0,0,0,0,0,0,0,0,0,7,7,4,7,0,5,4,0,4,5,0,0,0,0,0,0,0,1,0,0,8,8,0,0,5,0,2,0,8,7,0,8,8,7,0,0,0,0,5,0,0,0,0,0,0,0,0,0,0,0,0),[](0,0,0,0,0,3,0,0,3,0,3,5,7,0,0,0,0,0,0,2,0,0,3,0,0,0,0,0,0,0,0,0,5,3,0,9,0,4,9,0,8,2,0,0,9,0,7,0,5,0,0,0,9,2,0,0,0,0,0,3),[](0,1,0,0,8,0,8,0,0,2,0,4,8,0,0,7,0,9,9,7,0,0,0,0,0,0,5,0,3,0,0,0,4,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,3,0,0,0,4,0,0,0,0,0,0),[](2,0,7,1,3,0,2,6,8,0,0,0,1,0,0,4,0,4,0,9,3,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,6,5,6,0,1,0,0,1,0,0,0,0,5,0,0,0,0,0,0,0,0,0,0),[](8,7,3,0,6,4,0,9,0,8,0,9,6,0,0,5,0,0,0,0,0,0,7,7,0,0,0,0,0,0,0,0,0,0,0,5,0,5,0,0,2,0,0,1,7,4,3,0,5,0,0,0,0,8,7,8,1,2,0,0),[](0,1,0,0,3,0,5,0,0,9,0,0,9,0,0,8,0,4,9,9,8,6,0,0,0,0,0,9,1,0,8,0,0,0,0,0,0,0,4,0,0,0,4,0,0,0,0,0,2,0,2,0,4,0,0,6,8,9,0,0),[](0,0,0,0,0,0,0,0,0,1,0,0,4,0,1,8,2,0,0,2,0,0,0,0,0,0,0,0,0,0,3,6,6,0,4,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7,4),[](0,0,0,0,6,0,0,0,0,5,2,0,0,0,0,0,0,0,0,0,6,7,0,0,0,0,0,0,0,0,0,3,0,0,0,6,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,6,0,0,0,8),[](0,0,0,0,0,5,0,0,9,0,0,9,0,0,0,2,9,4,0,0,0,0,1,9,8,0,5,5,7,0,0,7,3,0,8,7,5,9,0,5,0,0,0,0,0,0,7,0,0,5,0,0,3,2,0,0,0,0,0,0),[](8,0,0,1,0,3,5,0,0,0,0,0,0,0,9,0,7,0,0,0,0,4,9,0,0,0,0,0,8,0,0,0,0,0,0,0,0,0,0,0,0,0,2,0,9,0,6,0,3,0,7,9,7,0,0,0,0,0,8,1),[](6,0,4,0,0,0,0,0,0,6,0,4,0,0,0,0,0,0,0,0,0,2,1,0,0,3,2,0,0,0,0,0,1,0,0,6,4,1,0,8,9,8,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0)),
        maxflow(A, 1, 60).