#include <iostream>
#include <algorithm>
#include <utility>
#include <string>
#include <vector>
#include <set>
#include <stack>
#include <queue>
#include <map>
#include <math.h>
#include <string.h>
#include <iomanip>
#include <numeric>
#include <cstdlib>
#include <cstdint>
#include <cmath>
#include <functional>
#include <limits>
#include <cassert>

using namespace std;

/* template */

using ll = long long;

void debug_out() { std::cout << std::endl; }
 
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cout << H << " ";
  debug_out(T...);
}

#ifdef LOCAL
#define debug(...) cout << "debug: "; debug_out(__VA_ARGS__)
#else
#define debug(...) 
#endif

#define rep(i, a, n) for (int i = (int)(a); i < (int)(n); i++)
#define rrep(i, a, n) for (int i = ((int)(n-1)); i >= (int)(a); i--)
#define Rep(i, a, n) for (long long i = (long long)(a); i< (long long)(n); i++)
#define RRep(i, a, n) for (long long i = ((long long)(n-1ll)); i>=(long long)(a); i--)
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()

template <typename T>
std::ostream& operator<<(std::ostream& os, std::vector<T> vec) {
  for (std::size_t i = 0; i < vec.size(); i++)os << vec[i] << (i + 1 == vec.size() ? "" : " ");
  return os;
}

struct Edge{
    int to;
    int weight;
    Edge(int t, int w) : to(t), weight(w){ }
};

struct edge{
    int from;
    int to;
    ll weight;
    edge(int f,int t,ll w) : from(f), to(t), weight(w){ }
};


using Graph = vector<vector<Edge>>;
using graph = vector<vector<int>>;
using edges = vector<edge>;

template <class T>
inline bool chmin(T &a, T b){
    if (a > b){
        a = b;
        return true;
    }
    return false;
}

template <class T>
inline bool chmax(T &a, T b){
    if (a < b){
        a = b;
        return true;
    }
    return false;
}

template <class T>
T lcm(T a, T b){
    return (a*b)/gcd(a,b);
}

bool isPalindrome(string s){
    string t = s;
    reverse(all(t));
    return s==t;
}

constexpr ll LNF = 1e15+7;

constexpr int INF = 1e9+7;

vector<int> dx = {-1,0,1,0,-1,1,-1,1};
vector<int> dy = {0,-1,0,1,1,-1,-1,1};

/* template */

struct BellmanFord{
    private:
      int n;
      bool negative = false;
      const ll LNF = (1LL<<60);
      vector<bool> used;
      vector<ll> d;
      Graph g;

      void dfs(int v){
          if(used[v]) return;
          used[v] = true;
          for(auto &nv: g[v]){
              dfs(nv.to);
          }
      }
    
    public:

      BellmanFord(int n,Graph &g) : n(n),g(g),used(n,false){}

      void build(int from){
          d.assign(n,LNF);
          d[from] = 0;
          for(int i = 0; i<n; i++){
              for(int v = 0; v<n; v++){
                  for(auto &nv: g[v]){
                      if(d[nv.to]>d[v]+nv.weight){
                          d[nv.to] = d[v]+nv.weight;
                      }
                  }
              }
          }
      }
      
      bool build(int from, int to){
          d.assign(n,LNF);
          vector<bool> reach(n,false);
          for(int i = 0; i<n; i++){
              used.assign(n,false);
              dfs(i);
              reach[i] = used[to];
          }
          d[from] = 0ll;
          for(int i = 0; i<n; i++){
              bool update = false;
              for(int v = 0; v<n; v++){
                  for(auto &nv: g[v]){
                      if(!reach[v] || !reach[nv.to] || d[v]==LNF) continue;
                      if(d[nv.to]>d[v]+nv.weight){
                          d[nv.to] = d[v]+nv.weight;
                          update = true;
                      }
                  }
              }
              if(!update) break;
              if(i==n-1){
                  return negative=true;
              }
          }
          return negative=false;
      }

      bool find_negative_loop(int s){
          vector<ll> dict(n,0ll);
          for(int i = 0; i<n; i++){
              for(int v = 0; v<n; v++){
                  for(auto &nv: g[v]){
                      if(dict[nv.to]>dict[v]+nv.weight){
                          dict[nv.to] = dict[v]+nv.weight;
                          if(i==n-1) return true;
                      }
                  }
              }
          }
          return false;
      }

      ll operator[](int index){return d[index];}
};

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n,m; cin >> n >> m;
    Graph g(n);
    rep(i,0,m){
        int a,b; ll c; cin >> a >> b >> c;
        a--; b--;
        g[a].emplace_back(b,-c);
    }
    BellmanFord bell(n,g);
    if(bell.build(0,n-1)){
        cout << "inf" << endl;
    }
    else{
        cout << -bell[n-1] << endl;
    }
}

Measured memory_bytes: 384