#include <bits/stdc++.h>
using namespace std;
int a[5000005],b[5000005],cha[5000005];

int main() {
	int n, p;
	scanf("%d%d", &n, &p);
	for(int i = 1; i <= n; i++) {
		scanf("%d", &a[i]);
		if(i == 1) cha[i] = a[i];
		else cha[i] = a[i]-a[i-1];
	}
	for(int i = 1; i <= p; i++) {
		int x,y,z;
		scanf("%d%d%d", &x,&y,&z);
		cha[x] += z;cha[y+1] += z;
		
	}
	int base = cha[1];
	int tmp,minn;
	
	for(int i = 1; i <= n; i++) {
		
		if(i == 1) {tmp = base;minn = tmp;}
		else{
			tmp += cha[i];
			if(tmp < minn) minn = tmp;
		}
	}
	printf("%d", minn);
	return 0;
	
}