#include <bits/stdc++.h>
using namespace std;
#define db(x) cerr<<#x<<(x)<<"\n"
#define db1(x) cerr<<#x<<(x)<<" "
#define rep(i,a,b) for(auto i=(a);i<=(b);i++)
#define ll long long
const int N = 1e5+10;
int n,m;
ll x[N],id[N],a[N],na[N];
int cnt[N];
void solve(){
    ll now=0,res=0,fu=0;
    cin>>n>>m;
    for(int i=1;i<=n;i++)cin>>a[i];
    x[0]=0;
    for(int i=1;i<=m;i++){
        cin>>x[i]>>id[i];
        cnt[id[i]]++;
    }
    for(int i=1;i<=n;i++){
       res+=a[i];
    }
    int j;
    for(j=1;j<=m;j++){
        ll d=x[j]-x[j-1];
        if(fu+d>res)break;
        if(a[id[j]]>=fu+d){
            fu=0;
        }else if(a[id[j]]>=fu){
            fu=fu+d-a[id[j]];
        }else{
            fu=fu-a[id[j]]+d;
        }
    }
    j--;
    cout<<x[j]-fu+res<<endl;
}
int main()
{
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    int _ ;cin>>_;while(_--)solve();
}