#include <bits/stdc++.h>
#define range(i, l, r) for(int (i) = (l); (i) < (r); (i)++)
#define reversed_range(i, l, r) for (int (i) = (r) - 1; (i) >= l; (i)--)
using namespace std;
template <typename T>
using vec = vector<T>;
using lint = long long;
using ulint = unsigned long long;
using pint = pair<int, int>;
using plint = pair<lint, lint>;

template <typename S, typename T>
ostream& operator <<(ostream& os, pair<S, T> p) {
    os << "(";
    os << p.first << ", " << p.second;
    return os << ")";
}

template <typename T>
ostream& operator <<(ostream& os, vec<T> v) {
    os << "[";
    for (int i = 0; i < v.size() - 1; i++) {
        os << v.at(i) << ", ";
    }
    return os << v.at(v.size() - 1) << "]";
}

template <typename T>
ostream& operator <<(ostream& os, set<T>& s) {
    os << "{";
    auto it_first_item = s.begin();
    cout << *it_first_item;
    for (auto it = ++it_first_item; it != s.end(); it++) {
        cout << ", " << *it;
    }
    return cout << "}";
}

template <typename T>
ostream& operator <<(ostream& os, unordered_set<T>& s) {
    os << "{";
    auto it_first_item = s.begin();
    cout << *it_first_item;
    for (auto it = ++it_first_item; it != s.end(); it++) {
        cout << ", " << *it;
    }
    return cout << "}";
}

template <typename K, typename V>
ostream& operator <<(ostream& os, map<K, V> m) {
    os << "{";
    auto it_first_item = m.begin();
    cout << it_first_item->first << ": " << it_first_item->second;
    for (auto it = ++it_first_item; it != m.end(); it++) {
        cout << ", " << it->first << ": " << it->second;
    }
    return os << "}";
}

template <typename K, typename V>
ostream& operator <<(ostream& os, unordered_map<K, V> m) {
    os << "{";
    auto it_first_item = m.begin();
    cout << it_first_item->first << ": " << it_first_item->second;
    for (auto it = ++it_first_item; it != m.end(); it++) {
        cout << ", " << it->first << ": " << it->second;
    }
    return os << "}";
}

bool influential_negative_cycle_exists(vec<vec<plint>>& adj, lint s, vec<lint>& d, vec<lint> parent) {
    lint num_nodes = adj.size();
    range(_, 0, num_nodes) {
        range(i, 0, num_nodes) {
            for (const auto edge : adj.at(i)) {
                lint neighbor = edge.first, cost = edge.second;
                if (d.at(neighbor) > d.at(i) + cost) {
                    d.at(neighbor) = d.at(i) + cost;
                    parent.at(neighbor) = i;
                }
            }
        }
    }
    lint score = d.at(num_nodes - 1);
    range(_, 0, num_nodes) {
        range(i, 0, num_nodes) {
            for (const auto edge : adj.at(i)) {
                lint neighbor = edge.first, cost = edge.second;
                if (d.at(neighbor) > d.at(i) + cost) {
                    d.at(neighbor) = d.at(i) + cost;
                    parent.at(neighbor) = i;
                }
            }
        }
    }
    return !(score == d.at(num_nodes - 1));
}

int main() {
    cin.tie(0); cout.tie(0);
    ios::sync_with_stdio(false);
    lint N, M;
    cin >> N >> M;
    vec<vec<plint>> adj(N, vec<plint>());
    range(i, 0, M) {
        lint a, b, c;
        cin >> a >> b >> c;
        a--; b--; c *= -1;
        adj.at(a).emplace_back(b, c);
    }
    vec<lint> d(N, 1LL << 62), parent(N, -1);
    d.at(0) = 0;
    if (influential_negative_cycle_exists(adj, 0, d, parent)) {
        cout << "inf" << "\n";
    } else {
        cout << d.at(N - 1) * -1 << "\n";
    }
}

Measured memory_bytes: 384