c  The total flow:
s 4

c flow values:
f 0 1 4
f 1 2 4
f 2 3 2
f 2 4 2
f 3 1 0
f 3 6 2
f 4 5 3
f 5 6 0
f 5 7 3
f 6 4 1
f 6 7 1