#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
istream &operator>>(istream &is, modint &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint &a) { return os << a.val(); }
istream &operator>>(istream &is, modint998244353 &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint998244353 &a) { return os << a.val(); }
istream &operator>>(istream &is, modint1000000007 &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint1000000007 &a) { return os << a.val(); } 

typedef long long ll;
typedef vector<vector<int>> Graph;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define FOR(i,l,r) for (int i = l;i < (int)(r); i++)
#define rep(i,n) for (int i = 0;i < (int)(n); i++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define my_sort(x) sort(x.begin(), x.end())
#define my_max(x) *max_element(all(x))
#define my_min(x) *min_element(all(x))
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const int INF = (1<<30) - 1;
const ll LINF = (1LL<<62) - 1;
const int MOD = 998244353;
const int MOD2 = 1e9+7;
const double PI = acos(-1);
vector<int> di = {1,0,-1,0};
vector<int> dj = {0,1,0,-1};

#ifdef LOCAL
#  include <debug_print.hpp>
#  define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define debug(...) (static_cast<void>(0))
#endif

struct Edge{
    int from, to;
    ll cost;
};
vector<bool> bellman_ford(int st, vector<ll> &dist, vector<Edge> & edges){
    int N = dist.size();
    for(int i=0;i<N;i++) dist[i] = -LINF;
    dist[st] = 0;
    rep(i,N-1){
        for(auto e: edges){
            if (dist[e.to] < dist[e.from] + e.cost){
                dist[e.to] = dist[e.from] + e.cost;
            }
        }
    }
    vector<bool> update(N, false);
    rep(i,N-1){
        for(auto e: edges){
            if (dist[e.to] < dist[e.from] + e.cost){
                dist[e.to] = dist[e.from] + e.cost;
                update[e.to] = true;
            }
        }
    }
    // 負閉路
    return update;
}

int main(){
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    int N, M; cin >> N >> M;
    vector<ll> A(N);
    rep(i,N) cin >> A[i];

    vector<Edge> edges;
    rep(i,M){
        int a, b; cin >> a >> b;
        a--;
        b--;
        ll c; cin >> c;
        edges.push_back(Edge{a + N, b, -c});
    }
    rep(i,N) edges.push_back(Edge{i, i + N, A[i]});

    vector<ll> dist(2 * N, -LINF);
    vector<bool> f = bellman_ford(0, dist, edges);
    debug(f);
    if(!f[2 * N - 1]){
        cout << dist[2 * N - 1] << endl;
    }
    else{
        cout << "inf" << endl;
    }
}