#include <bits/stdc++.h>
using namespace std;
int n, p;
int a[5123456];
int d[5123456];
int main()
{
    cin >> n >> p;
    for (int i = 1; i <= n; i++)
        cin >> a[i];
    for (int i = 1; i <= n; i++)
        d[i] = a[i] - a[i - 1];
    while (p--)
    {
        int l, r, x;
        cin >> l >> r >> x;
        d[l] += x;
        d[r + 1] -= x;
    }
    int ans = d[1];
    a[0] = 0;
    for (int i = 1; i <= n; i++)
    {
        a[i] = a[i - 1] + d[i];
        ans = min(ans, a[i]);
    }
    cout << ans << "\n";
    return 0;
}