#include <bits/stdc++.h>
#define int long long
#define iosy ios::sync_with_stdio(0),cin.tie(0),cout.tie(0)
using namespace std;
const int N = 1e5+10; 

void solve(){
    int n,m;cin>>n>>m;
    int sum=0;
    map<int,int> mp;
    vector<int> a(n+1);
    for(int i=1;i<=n;i++){
        cin>>a[i];sum+=a[i];
        mp[i]=a[i];
    }
    vector<int> x(m+5,0),t(m+5,0);
    for(int i=1;i<=m;i++){
        int a,b;cin>>a>>b;
        x[i]=a,t[i]=b;
    }
    vector<int> temp(m+5,0);
    for(int i=1;i<=m;i++){
        if(sum<x[i])break;
        else{
            if(x[i]-x[i-1]>=a[t[i]]-temp[i]){
                sum+=mp[t[i]];
                temp[i]+=(x[i]-x[i-1]-a[t[i]]);
            }else{
                sum+=(x[i]-x[i-1]);
                temp[i]-=temp[i-1];
            }
        }
    }
    cout<<sum<<"\n";
}

signed main()
{
	iosy;int _t=1;
	cin>>_t;
	while(_t--){solve();}
	return 0;
}