#include<bits/stdc++.h> 
using namespace std;
const int N = 1e6 + 5; 
int n, m, r[N], cha[N];
int main(){
	cin >> n >> m;
	for(int i = 1 ; i <= n ; i++){
		cin >> r[i];
	}
	for(int i = 1 ; i <= m ; i++){
		int a, b, c;
		cin >> a >> b >> c;
		cha[b] += a;
		cha[c + 1] -= a;
	}
	int sum, sum_1 = 0;
	for(int i = 1 ; i <= m; i++){
		sum = sum_1 + cha[i];
		if(sum > r[i]){
			cout << "-1" << "\n";
			cout << i << "\n";
			return 0;
		}
		sum_1 = sum;
	}
	cout << "0\n";
	return 0;
}