#include<bits/stdc++.h>
using namespace std;
int n,a[100001],b[100001],k,ans=INT_MAX;
int main(){
	cin>>n>>k;
	for(int i=1;i<=n;i++){
		cin>>a[i];
		b[i]=a[i]-a[i-1];
	}
	for(int i=1;i<=k;i++){
		int l,r,water;
		cin>>l>>r>>water;
		b[l]+=water;
		b[r+1]-=water;
	}
	for(int i=1;i<=n;i++){
		b[i]=b[i]+b[i-1];
	}
	for(int i=1;i<=n;i++){
		ans=min(ans,b[i]);
	}
	cout<<ans;
}