#include<iostream>
#include<cstdio>
#define ll long long
using namespace std;
int n,m;
int a[1000005],b[1000005];
int d,s,t;
int main(){
    freopen("classrooms.in","r",stdin);
    freopen("classrooms.out","w",stdout);
    scanf("%d%d",&n,&m);
    for(int i=1;i<=n;i++){
        scanf("%lld",&a[i]);
        b[i]=a[i]-a[i-1];
    }
    for(int i=1;i<=m;i++){
        scanf("%d%d%d",&d,&s,&t);
        b[s]-=d,b[t+1]+=d;
        for(int j=1;j<=n;j++){
            a[j]=b[j]+a[j-1];
        }
        for(int j=s;j<=t;j++){
            if(a[j]<0){
                printf("-1\n%d",i);
                return 0;
            }
        }
    }
    printf("0");
    return 0;
}