#include<bits/stdc++.h>
using namespace std;
const int N=1e5;
int n,m;
int a[N],b[N];
int main() {
	int n,m,min=1e9;
	cin>>n>>m;
	for(int i=1; i<=n; i++) {
		cin>>a[i];
		b[i]=a[i]-a[i-1];
	}
	int l,r,c;
	while(m--) {
		cin>>l>>r>>c;
		b[l]+=c;
		b[r+1]-=c;
	}

	for(int i=1; i<=n; i++) {
		b[i]+=b[i-1];
		if(b[i]<=min) {
			min=b[i];
		}
	}
	cout<<min;
	return 0;
}