public void Solve()
{
//ABC061 D
int N = NextInt(), M = NextInt();
var bf = new BellmanFord(N);
M.REP(i => {
int ai = NextInt() - 1, bi = NextInt() - 1, ci = NextInt();
bf.Add(ai, bi, -ci);
});
bf.Run(0);
if (bf.HasCycle)
{
"inf".WL();
}
else
{
(-bf.Distance[N - 1]).WL();
}
return;
}