rt

#include <bits/stdc++.h>
using namespace std;
int d[5000005],a[5000005],minn=0x7f7f7f7f;
int n,p,x,y,z;
int main()
{
	cin>>n>>p;
	for(int i=1;i<=n;i++){
        cin>>a[i];
        d[i]=a[i]-a[i-1];
	}
	for(int i=1;i<=p;i++){
        cin>>x>>y>>z;
        d[x]+=z;
        d[y+1]+=z;
	}
	for(int i=1;i<=n;i++){
        d[i]=d[i-1]+d[i];
        minn=min(minn,d[i]);
	}
	cout<<minn<<endl;
	return 0;
}