#include<bits/stdc++.h>
using  namespace std;
int a[10005],d[10005];
int main(){
    int n,p;
    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){
        int x,y,z;
        cin>>x>>y>>z;
        d[x]+=z;
        d[y+1]-=z;
    }
    int minn=INT_MAX,t=0;
    for(int i=1;i<=n;++i){
        t+=d[i];
        minn=min(t,minn);
    }
    cout<<minn;
    return 0;
}