#include <iostream>
using namespace std;

int sum[5000005];
int n,m; 
signed main()
{
	ios::sync_with_stdio(false);
	cin.tie(0),cout.tie(0);
	cin>>n>>m;
	for(int i = 1;i<=n;i++){
		cin>>sum[i];
		sum[i]-=sum[i-1];
	}
	for(int i = 1;i<=m;i++){
		int a,b,c;
		cin>>a>>b>>c;
		sum[a]+=c;
		sum[b+1]-=c;
	}
	int minn = 0x7fffffff;
	for(int i = 1;i<=m;i++){
		sum[i]+=sum[i-1];
		minn = min(minn,sum[i]);
	}
	cout<<minn;
	return 0;
}

#2 和 #5 WA