#include <bits/stdc++.h>
using namespace std;
#define fileIO(s) freopen(s".in", "r", stdin), freopen(s".out", "w", stdout);
#define y1 why_not_can_not_use_y1
typedef long long ll;
typedef unsigned long long ull;
constexpr int inf = 0x3f3f3f3f;
constexpr int MAXN = 1145140;

int inline width(ll n){
    return floor(log10(n)) + 1;
}

int n, m;
int r[MAXN], d, s, t;
int dif[MAXN], sum[MAXN];

int main(){
    
    cin >> n >> m;
    for(int i = 1; i <= n; i++){
        cin >> r[i];
    }
    for(int i = 1; i <= m; i++){
        cin >> d >> s >> t;
        dif[s] -= d;
        dif[t + 1] += d;
    }
    for(int i = 1; i <= n; i++){
        sum[i] += dif[i];
        if(sum[i] + r[i] < 0){
            cout << -1 << endl << i;
            return 0;
        }
    }
    cout << 0;
    
    return 0;
}