#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, a, b) for(int i = a; i < b; i++)
#define rrep(i, a, b) for(int i = b - 1; i >= a; i--)
#define ALL(a) a.begin(), a.end()
#define pii pair<int,int>
#pragma GCC optimize("Ofast")
#define pcnt __builtin_popcount
#define buli(x) __builtin_popcountll(x)
#define pb push_back
#define mp make_pair
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );
template<class T>bool chmax(T &a, const T &b) {if(a<b){a = b; return 1;} return 0; };
template<class T>bool chmin(T &a, const T &b) {if(a>b){a = b; return 1;} return 0; };
inline void IN(void){return;}
template <typename First, typename... Rest> void IN(First& first, Rest&... rest){cin >> first;IN(rest...);return;}
inline void OUT(void){cout << "\n";return;}
template <typename First, typename... Rest> void OUT(First first, Rest... rest){cout << first << " ";OUT(rest...);return;}
const double EPS = 1e-9;
const int mod = 1e9 + 7;
long long lcm(ll a, ll b){return a * b / __gcd(a,b);}
struct IoSetup { IoSetup() {
    cin.tie(nullptr);ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
} } iosetup;
template< int mod > struct ModInt {
    int x; ModInt() : x(0) {}
    ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}
    ModInt &operator+=(const ModInt &p) {if((x += p.x) >= mod) x -= mod;return *this;}
    ModInt &operator-=(const ModInt &p) {if((x += mod - p.x) >= mod) x -= mod;return *this;}
    ModInt &operator*=(const ModInt &p) {x = (int) (1LL * x * p.x % mod);return *this;}
    ModInt &operator/=(const ModInt &p) {*this *= p.inverse();return *this;}
    ModInt operator-() const { return ModInt(-x); }
    ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }
    ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }
    ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }
    ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }
    bool operator==(const ModInt &p) const { return x == p.x; }
    bool operator!=(const ModInt &p) const { return x != p.x; }
    ModInt inverse() const {int a = x, b = mod, u = 1, v = 0, t;
    while(b > 0) { t = a / b; swap(a -= t * b, b); swap(u -= t * v, v); }return ModInt(u);}
    ModInt pow(int64_t n) const {ModInt ret(1), mul(x); while(n > 0) {if(n & 1) ret *= mul;mul *= mul;n >>= 1;}return ret;}
    friend ostream &operator<<(ostream &os, const ModInt &p) { return os << p.x;}
    friend istream &operator>>(istream &is, ModInt &a) { int64_t t; is >> t; a = ModInt< mod >(t); return (is); }
    static int get_mod() { return mod; }
}; using modint = ModInt< mod >;

struct edge{ll from, to, cost;};

static const long long INF = 1LL<<60;
static const int MAX_E = 100000;
static const int MAX_V = 10000;

edge es[MAX_E];//辺

ll d[MAX_V];//最短距離
int V, E;//Vは頂点数,Eは辺の数

//s番目の頂点から各頂点への最短距離を求める
void shortest_path(int s, int t){
    for(int i = 0; i < V; i++) d[i] = INF;
    d[s] = 0;
    while(true){
        bool update = false;
        for(int i = 0; i < E; i++){
            edge e = es[i];
            if(d[e.from] != INF && d[e.to] > d[e.from] + e.cost){
                d[e.to] = d[e.from] + e.cost;
                if(e.to == t) update = true;
            }
        }
        if(!update) break;
    }
}

//閉ループが存在するか判定
bool find_negative_loop(int k){
    memset(d, 0, sizeof(d));

    for(int i = 0; i < V; i++){
        for(int j = 0; j < E; j++){
            edge e = es[j];
            if(d[e.to] > d[e.from] + e.cost){
                d[e.to] = d[e.from] + e.cost;

                //n回目にも更新があるなら負の閉路が存在する
                if(i == V - 1 && e.to == k) return true;
            }
        }
    }
    return false;
}

int main(){
    iosetup;
    IN(V, E);
    rep(i, 0, E){
        ll a, b, c; IN(a, b, c);a--, b--;
        es[i] = (edge){a, b, -c};
    }
    if(find_negative_loop(V-1)){
        cout << "inf" << endl;
        return 0;
    };
    shortest_path(0, V - 1);

    cout << -d[V-1] << endl;

    return 0;
}

Measured memory_bytes: 384