#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int N = 6 * int(1e6);
int n, p, ans = 1e9;
int d[N], a[N];

int main() {
	cin >> n >> p;
	for (int i = 1; i <= n; i++) {
		cin >> d[i];
		d[i] = d[i] - d[i - 1];
	}
	for (int i = 1; i <= p; i++) {
		int x, y, z;
		cin >> x >> y >> z;
		d[x] += z;
		d[y + 1] -= z;
	}
	for (int i = 1; i <= n; i++) {
		a[i] = d[i] + a[i - 1];
		ans = min(ans, a[i]);
	}

	cout << ans;
	return 0;
}