#include <bits/stdc++.h>

using namespace std;

ifstream fin("bellmanford.in");
ofstream fout("bellmanford.out");

int i,n,m,x,y,a,b,c,s,nr,mn,sol[50005];
vector <pair<int,int>> t[50005];
bool viz[50005];
queue <int> coada;

void bfs()
{
    int i,k;
    coada.push(1);
    sol[1]=1;
    while (!coada.empty())
    {
        k=coada.front();
        viz[k]=0;
        coada.pop();
        for (i=0; i<t[k].size(); i++)
        {
            if (t[k][i].second+sol[k]<sol[t[k][i].first] || sol[t[k][i].first]==0)
            {
                sol[t[k][i].first]=t[k][i].second+sol[k];
                if (viz[t[k][i].first]==0)
                {
                    coada.push(t[k][i].first);
                    viz[t[k][i].first]=1;
                }
            }
        }
    }
}

int main()
{
    fin>>n>>m;
    for (i=1; i<=m; i++)
    {
        fin>>a>>b>>c;
        t[a].push_back(make_pair(b,c));
    }

    //bfs();

    //for (i=2; i<=n; i++)
      //  if (sol[i]==0) fout<<0<<" "; else fout<<sol[i]-1<<" ";
    cout<<"Ciclu negativ!";
    return 0;
}