#include <iostream>
#include <cmath>
using namespace std;
int n,p;
int s1[1000806],f[1000806];
int x,y,z;int Min=100000086;
int main(){
    cin>>n>>p;
    for(int i=1;i<=n;i++){
        cin>>s1[i];
        f[i]=s1[i]-s1[i-1];
    }
    while(p--){
        cin>>x>>y>>z;
        f[x]+=z;
        f[y+1]-=z;
    }
    for(int i=1;i<=n;i++){
        s1[i]=f[i]+s1[i-1];
        Min=min(Min,s1[i]);
    }
    cout<<Min<<endl;
}