```cpp
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 1e6 + 10;

int n, m;
ll r[MAXN];
ll d[MAXN], s[MAXN], t[MAXN];
ll diff[MAXN];
bool check(int mid)
{
    memset(diff, 0, sizeof(diff));
    for(int i = 1; i <= mid; ++i)
    {
        diff[s[i]] += d[i];
        diff[t[i] + 1] -= d[i];
    }
    ll sum = 0;
    for(int i = 1; i <= n; ++i)
    {
        sum += diff[i];
        if(sum > r[i]) return false;
    }
    return true;
}
inline ll read()
{
    ll x = 0, f = 1;
    char ch = getchar();
    while(ch < '0' || ch > '9')
    {
        if(ch == '-') f = -1;
        ch = getchar();
    }
    while(ch >= '0' && ch <= '9')
    {
        x = (x << 3) + (x << 1) + (ch ^ 48);
        ch = getchar();
    }
    return x * f;
}

int main()
{
    n = read(), m = read();
    for(int i = 1; i <= n; ++i) r[i] = read();
    for(int i = 1; i <= m; ++i)
    {
        d[i] = read();
        s[i] = read();
        t[i] = read();
    }

    int l = 1, r = m, ans = 0;
    while(l <= r)
    {
        int mid = (l + r) / 2;
        if(check(mid))
        {
            l = mid + 1;
        }
        else
        {
            ans = mid;
            r = mid - 1;
        }
    }
    if(ans == 0) cout << 0 << endl;
    else
    {
        cout << -1 << endl;
        cout << ans << endl;
    }
    return 0;
}