#include<bits/stdc++.h>
#define int long long
#define N 100005
using namespace std;
int T;
int n,m;
int a[N];
int x[N],t[N];
void sol(){
    scanf("%lld %lld",&n,&m);
    int sum=0,p=0;
    for(int i=1;i<=n;i++) scanf("%lld",&a[i]),sum+=a[i];
    for(int i=1;i<=m;i++) scanf("%lld %lld",&x[i],&t[i]);
    x[m+1]=1e18;
    for(int i=1;i<=m+1;i++){
        if(x[i-1]+sum-p<x[i]){printf("%lld\n",x[i-1]+sum-p);return;}
        p+=x[i]-x[i-1];
        p-=min(a[t[i]],p);
    }
}
signed main(){
    scanf("%lld",&T);
    while(T--) sol();
    return 0;
}