public static void Main(string[] args)
{
N = Input.NextInt();
M = Input.NextInt();
var nodes = Enumerable.Range(0, N).Select(n => new BellmanFord.Node()).ToArray();
var edges = new List <BellmanFord.Edge>();
for (int i = 0; i < M; i++)
{
var abc = Input.LineInt();
var a = abc[0] - 1;
var b = abc[1] - 1;
var c = -abc[2];
var ef = nodes[a].CreateEdge(nodes[b], c);
edges.Add(ef);
}
var search = new BellmanFord();
search.Search(nodes, edges, nodes[0]);
var negOfMaxCost = nodes[N - 1].MinDistance;
Console.WriteLine(negOfMaxCost == long.MinValue ? "inf" : (-negOfMaxCost).ToString());
}