//#include <bits/stdc++.h>

#include <iostream>
#include <algorithm>

#include <bitset>
#include <vector>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <stack>
#include <queue>
#include <deque>
#include <cstring>
#include <string>
#include <utility>
#include <array>
#include <complex>
#include <valarray>

#include <cassert>
#include <cmath>
#include <functional>
#include <iomanip>
#include <chrono>
#include <random>
#include <numeric>


using namespace std;
#define int long long

typedef long long ll;
typedef unsigned long long ull;
//typedef unsigned __int128 HASH;
typedef pair<int,int> pii;
typedef pair<ll, ll> pll;
typedef pair<ull, ull> pullull;
typedef pair<ll,int> plli;
typedef pair<double, int> pdbi;
typedef pair<int,pii> pipii;
typedef pair<ll,pll> plpll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<pii> vpii;
typedef vector<vector<int>> mat;

#define rep(i,n) for (int i=0;i<(n);i++)
#define rep2(i,a,b) for (int i=(a);i<(b);i++)
#define rrep(i,n) for (int i=(n);i>0;i--)
#define rrep2(i,a,b) for (int i=(a);i>b;i--)
#define pb push_back
#define fi first
#define se second
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()

const ll hmod1 = 999999937;
const ll hmod2 = 1000000000 + 9;
const int INF = 1<<30;
const ll INFLL = 1LL<<62;
const double EPS = 1e-12;
const ll mod = 1000000000 + 7;
const int dx4[4] = {1, 0, -1, 0};
const int dy4[4] = {0, 1, 0, -1};
const int dx8[8] = {1, 1, 1, 0, 0, -1, -1, -1};
const int dy8[8] = {0, 1, -1, 1, -1, 0, 1, -1};
const double pi = 3.141592653589793;

#define addm(X, Y) (X) = ((X) + ((Y) % mod) + mod) % mod
#define inside(y, x, h, w) (0 <= (y) && (y) < (h) && 0 <= (x) && (x) < (w)) ? true : false

struct edge {int from, to, cost;};
vector<edge> es;
ll d[1005];                     //最短経路距離
int n, m;

bool shortpath(int s, int n) {
    for (int i = 0; i < n; i++) {
        d[i] = INFLL;
    }
    d[s] = 0;
    int cnt = 0;
    while (true) {
        bool update = false;
        for (auto e : es) {
            if (d[e.from] != INFLL && d[e.to] > d[e.from] + e.cost) {
                d[e.to] = d[e.from] + e.cost;
                update = true;
            }
        }
        if (!update) break;
        cnt++;
        if (cnt == n) break;
    }
    if (cnt == n) return true;
    else return false;
}


vector<bool> find_negative_loop(int s, int n) {
    vector<bool> negative(n);
    for (int i = 0; i < n; i++) {
        for (auto e : es) {
            if (d[e.from] != INFLL && d[e.to] > d[e.from] + e.cost) {
                d[e.to] = d[e.from] + e.cost;
                negative[e.to] = true;
            }
            //if (negative[e.from]) negative[e.to] = true;
        }
    }
    return negative;
}

signed main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> n >> m;
    rep(i, m) {
        int a, b, c;
        cin >> a >> b >> c;
        a--; b--;
        es.push_back({a, b, -c});
    }
    if (shortpath(0, n)) {
        vector<bool> ng = find_negative_loop(0, n);
        if (ng[n - 1]) cout << "inf" << endl;
        else cout << -d[n - 1] << endl;
    }
    else cout << -d[n - 1] << endl;
}

Measured memory_bytes: 384