#include<bits/stdc++.h>
using namespace std;
	int a[100010],d[100010],c[100010];
int main(){
	int n,p;
	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 x,y,z;
		cin>>x>>y>>z;
		d[x]+=z;
		d[y+1]-=z;
	}
	int minn=300;
	for(int i=1;i<=n;i++){
		c[i]=c[i-1]+d[i];
		if(c[i]<minn)minn=c[i];
	}
	cout<<minn;
	return 0;
}