#include<bits/stdc++.h>
#define ll long long
using namespace std;
ll n,m,diff[1000001],s[1000001];
int main()
{
	 cin>>n>>m;
	 for(int i=0;i<n;i++)cin>>s[i];
	 diff[0]=s[0];
	 for(int i=1;i<n;i++)diff[i]=s[i]-s[i-1];
	 while(m--)
	 {
	 	ll x,y,k;
	 	cin>>x>>y>>k;
	 	diff[x-1]+=k;
	 	if(y!=n)diff[y]-=k;
	 }
	 ll sum=0,minn=1e15;
	 for(int i=0;i<n;i++)
	 {
	 	s[i]=sum+diff[i];
	 	sum+=diff[i];
	 	minn=min(minn,s[i]);
	} 
	cout<<minn;
	return 0;
}