#include<bits/stdc++.h>
using namespace std;
typedef long long LL;

const int N=1e5+10;
LL a[N],x[N],t[N];
LL man[N];

void solve()
{
    LL n,m;
    cin >> n >> m;
    
    memset(man,0,(sizeof (LL))*(n+5));
    
    LL sum=0;
    for(LL i=1;i<=n;i++)
    {
        cin >> a[i];
        sum+=a[i];
    }
    for(LL i=1;i<=m;i++)
    {
        cin >> x[i] >> t[i];
    }
    
    LL dis=0,ans=0;
    for(LL i=1;i<=m;i++)
    {
        LL d=x[i]-x[i-1];
        dis+=d;
        if(dis>sum) 
        {
            ans=x[i-1]+(sum-(dis-d));
            break;
        }
        LL bus=min(dis,min(x[i] - x[i - 1] -man[t[i]],a[t[i]]));
        dis-=bus;
        dis = max(dis , 0ll) ;
        man[t[i]]=x[i];
    }
    if(dis<=sum) ans=x[m]+(sum-dis);
    
    cout << ans << '\n';
}

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    
    int T;
    cin >> T;
    while(T--)
    {
        solve();
    }
    
    return 0;
}
/*
1
1 4
1
1 1
2 1
3 1
4 1

*/