#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define N 1000005

ll a[N], b[N];
struct P {
    int d, x, y;
} p[N];

int n, m;

bool check(int mid) {//肌肉👍
    memset(b, 0, sizeof(b));

    for (int j = 1; j <= mid; j++) {
        b[p[j].x] -= p[j].d;
        b[p[j].y + 1] += p[j].d;
    }

    for (int i = 1; i <= n; i++) {
        b[i] += b[i - 1];
        if (a[i] + b[i] < 0) return true;
    }
    return false;
}

int main() {
    
    cin >> n >> m;//唐人输入
    
    for (int i = 1; i <= n; i++) {
        cin >> a[i]; 
    }
    
    for (int j = 1; j <= m; j++) {
        cin >> p[j].d >> p[j].x >> p[j].y;
    }
    
    int l = 1, r = m + 1;
    while (l < r) {//二分之1
        int mid = (l + r) / 2; 
        if (check(mid)) {
            r = mid; 
        } else {
            l = mid + 1;
        }
    }
    
    if (l == m + 1) cout << 0; 
    else cout << -1 << "\n" << l; //乐子之输出
}