#include<bits/stdc++.h>
#include<atcoder/all>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
using namespace atcoder;
typedef long long ll;
typedef vector<int> vi;
typedef vector<long long> vl;
typedef vector<vector<int>> vvi;
typedef vector<vector<long long>> vvl;
typedef long double ld;
typedef pair<int, int> P;

ostream& operator<<(ostream& os, const modint& a) {os << a.val(); return os;}
template <int m> ostream& operator<<(ostream& os, const static_modint<m>& a) {os << a.val(); return os;}
template <int m> ostream& operator<<(ostream& os, const dynamic_modint<m>& a) {os << a.val(); return os;}
template<typename T> istream& operator>>(istream& is, vector<T>& v){int n = v.size(); assert(n > 0); rep(i, n) is >> v[i]; return is;}
template<typename U, typename T> ostream& operator<<(ostream& os, const pair<U, T>& p){os << p.first << ' ' << p.second; return os;}
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v){int n = v.size(); rep(i, n) os << v[i] << (i == n - 1 ? "\n" : " "); return os;}
template<typename T> ostream& operator<<(ostream& os, const vector<vector<T>>& v){int n = v.size(); rep(i, n) os << v[i] << (i == n - 1 ? "\n" : ""); return os;}

template<typename T> void chmin(T& a, T b){a = min(a, b);}
template<typename T> void chmax(T& a, T b){a = max(a, b);}

long long const INF = 1001001001001001001;
template<typename T>
struct Edge{
	T cost;
	int from, to;
	bool operator<(const Edge<T>& right) const{
		return this->cost < right.cost;
	}
};

template<typename T>
struct BellmanFord{
	bool initialized;
	int n;
	int m;
	vector<T> dist;
	vector<Edge<T>> G;
	BellmanFord(int _n) : initialized(false), n(_n), m(0), dist(_n, INF) {}
	void add_edge(int from, int to, T cost){
		G.push_back((Edge<T>){cost, from, to});
		m++;
	}
	void init(int start){
		initialized = true;
		sort(G.begin(), G.end());
		dist[start] = 0;
		rep(time, n + 5){
			bool change = false;
			rep(i, m){
				auto e = G[i];
				if(dist[e.from] + e.cost < dist[e.to]){
					dist[e.to] = dist[e.from] + e.cost;
					change = true;
				}
			}
			if(!change) break;
			if(change) if(time > n){
				rep(i, n) dist[i] = -INF;
				return;
			}
		}
	}
	T get_dist(int from, int to){
		if(!initialized) init(from);
		return dist[to];
	}
};

int main(){
	int n, m;
	cin >> n >> m;
	vector<long long> a(n);
	cin >> a;
	BellmanFord<long long> graph(2 * n);
	rep(i, n) graph.add_edge(i, n + i, -a[i]);
	vector<tuple<int, int, int>> G;
	vector<vector<int>> retro(n);
	rep(i, m){
		int u, v, c;
		cin >> u >> v >> c;
		u--; v--;
		G.emplace_back(u, v, c);
		retro[v].push_back(u);
	}
	vector<int> need(n);
	queue<int> q;
	q.push(n - 1);
	while(q.size()){
		int from = q.front(); q.pop();
		if(need[from]) continue;
		need[from] = 1;
		for(int to : retro[from]){
			q.push(to);
		}
	}
//	cout << need;
	for(auto [u, v, c] : G){
		if(need[u] == 1 and need[v] == 1) graph.add_edge(n + u, v, c);
	}
	long long ans = graph.get_dist(0, 2 * n - 1);
	if(ans == -INF) cout << "inf\n";
	else cout << -ans << "\n";
	return 0;
}