#include<bits/stdc++.h> 
using namespace std;
int n,m,a[200001],a1[200001],l,r,f,mi=INT_MAX;
int main(){
	memset(a,0,sizeof(a));
	memset(a1,0,sizeof(a1));
	cin>>n>>m;
	for(int i=1;i<=n;i++){
		cin>>a[i];
		a[i]-=a[i-1];
	}
	while(m--){
		cin>>l>>r>>f;
		a[l]+=f;
		a[r+1]-=f;
	}
	for(int i=1;i<=n;i++){
	    a1[i]=a[i]+a1[i-1];
	    mi=min(mi,a1[i]);
	}
	cout<<mi;
	return 0;
}