digraph foo {
rankdir = LR;
s;
1;
2;
3;
4;
5;
6;
t;
1->s [label="0,3"];
s->3 [label="0,1"];
3->s [label="0,2"];
2->1 [label="-10,2"];
4->1 [label="-15,2"];
2->4 [label="5,2"];
6->4 [label="0,2"];
t->6 [label="0,2"];
1->3 [label="20,1"];
t->2 [label="0,1"];
4->3 [label="-20,1"];
6->3 [label="-25,1"];
3->5 [label="10,1"];
t->4 [label="0,1"];
5->6 [label="15,1"];
t->6 [label="0,1"];
}