#include<bits/stdc++.h>
using namespace std;
const int N=5000010;
int a[N],b[N];
int main()
{
	ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	int n,p;
	cin>>n>>p;
	for(int i=1;i<=n;++i)
	{
		cin>>a[i];
	}
	for(int i=1;i<=n;++i)
	{
		b[i]=a[i]-a[i-1];
	}
	while(p--)
	{
		int x,y;
		cin>>x>>y;
		int k;
		cin>>k;
		b[x]+=k;
		b[y+1]-=k;
	}
	int min=1e9;
	for(int i=1;i<=n;++i)
	{
		b[i]+=b[i-1];
		if(min>b[i])
		{
			min=b[i];
		}
	}
	cout<<min;
	return 0;
}