#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=a;i>=b;i--)
#define fore(i,a) for(auto &i:a)
#define all(x) (x).begin(),(x).end()
//#pragma GCC optimize ("-O3")
using namespace std; void _main(); int main() { cin.tie(0); ios::sync_with_stdio(false); _main(); }
typedef long long ll; const int inf = INT_MAX / 2; const ll infl = 1LL << 60;
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 (b<a) { a = b; return 1; } return 0; }
//------------------------------------------------------------------------------
template<int MOD> struct ModInt {
    static const int Mod = MOD; unsigned x; ModInt() : x(0) { }
    ModInt(signed sig) { x = sig < 0 ? sig % MOD + MOD : sig % MOD; }
    ModInt(signed long long sig) { x = sig < 0 ? sig % MOD + MOD : sig % MOD; }
    int get() const { return (int)x; }
    ModInt &operator+=(ModInt that) { if ((x += that.x) >= MOD) x -= MOD; return *this; }
    ModInt &operator-=(ModInt that) { if ((x += MOD - that.x) >= MOD) x -= MOD; return *this; }
    ModInt &operator*=(ModInt that) { x = (unsigned long long)x * that.x % MOD; return *this; }
    ModInt &operator/=(ModInt that) { return *this *= that.inverse(); }
    ModInt operator+(ModInt that) const { return ModInt(*this) += that; }
    ModInt operator-(ModInt that) const { return ModInt(*this) -= that; }
    ModInt operator*(ModInt that) const { return ModInt(*this) *= that; }
    ModInt operator/(ModInt that) const { return ModInt(*this) /= that; }
    ModInt inverse() const { long long a = x, b = MOD, u = 1, v = 0;
        while (b) { long long t = a / b; a -= t * b; std::swap(a, b); u -= t * v; std::swap(u, v); }
        return ModInt(u); }
    bool operator==(ModInt that) const { return x == that.x; }
    bool operator!=(ModInt that) const { return x != that.x; }
    ModInt operator-() const { ModInt t; t.x = x == 0 ? 0 : Mod - x; return t; }
};
template<int MOD> ostream& operator<<(ostream& st, const ModInt<MOD> a) { st << a.get(); return st; };
template<int MOD> ModInt<MOD> operator^(ModInt<MOD> a, unsigned long long k) {
    ModInt<MOD> r = 1; while (k) { if (k & 1) r *= a; a *= a; k >>= 1; } return r; }
template<typename T, int FAC_MAX> struct Comb { vector<T> fac, ifac;
    Comb(){fac.resize(FAC_MAX,1);ifac.resize(FAC_MAX,1);rep(i,1,FAC_MAX)fac[i]=fac[i-1]*i;
        ifac[FAC_MAX-1]=T(1)/fac[FAC_MAX-1];rrep(i,FAC_MAX-2,1)ifac[i]=ifac[i+1]*T(i+1);}
    T aPb(int a, int b) { if (b < 0 || a < b) return T(0); return fac[a] * ifac[a - b]; }
    T aCb(int a, int b) { if (b < 0 || a < b) return T(0); return fac[a] * ifac[a - b] * ifac[b]; }
    T nHk(int n, int k) { if (n == 0 && k == 0) return T(1); if (n <= 0 || k < 0) return 0;
        return aCb(n + k - 1, k); }}; // nHk = (n+k-1)Ck : n is separator
typedef ModInt<1000000007> mint;
//------------------------------------------------------------------------------
using Weight = ll;

struct Edge
{
public:
    Edge(int src, int dst, Weight weight) : src(src), dst(dst), weight(weight) {}

    int src;
    int dst;
    Weight weight;
};

using Edges = vector<Edge>;
using Graph = vector<Edges>;

bool BellmanFord(const Graph& g, int s, vector<Weight>& dist, vector<int>& prev)
{
    const int n = g.size();
    dist.assign(n, infl);
    dist[s] = 0;
    prev.assign(n, -2);

    bool fuheiro = false;
    rep(k, 0, n)
    {
        rep(i, 0, n)
        {
            for (const auto& e : g[i])
            {
                if (dist[e.src] != infl && chmin(dist[e.dst], dist[e.src] + e.weight))
                {
                    prev[e.dst] = e.src;

                    if (k == n - 1)
                    {
                        dist[e.dst] = -infl;
                        if (e.dst == g.size() - 1)
                        {
                            fuheiro = true;
                        }
                    }
                }
            }
        }
    }
    return fuheiro;
}

void _main()
{
    int N, M;
    cin >> N >> M;
    Graph G(N);
    rep(i, 0, M)
    {
        int a, b;
        Weight c;
        cin >> a >> b >> c;
        --a; --b;
        G[a].emplace_back(a, b, -c);
    }

    vector<Weight> dist;
    vector<int> prev;
    if (BellmanFord(G, 0, dist, prev))
    {
        cout << "inf" << endl;
    }
    else
    {
        cout << -dist[N - 1] << endl;
    }
}


Measured memory_bytes: 384