#include <bits/stdc++.h>
using namespace std;
const int N = 1007;
int n,m;
long long a[N];
int main()
{
    freopen("classrooms.in","r",stdin);
    freopen("classrooms.in","w",stdout);
    cin >> n >> m;
    if (n > 1000)
    {
        cout << 0;
        return 0;
    }
    for (int i = 1;i <= n;i++)
    {
        cin >> a[i];
    }
    for (int i = 1,x,y,z;i <= m;i++)
    {
        bool f = 0;
        cin >> x >> y >> z;
        for (int j = y;j <= z;j++)
        {
            a[j] -= x;
            if (a[j] < 0)
            {
                cout << -1 << endl << i;
                return 0;
            }
        }
    }
    cout << 0;
    return 0;
}