#include <bits/stdc++.h>
using namespace std;
using ll = long long;

void solve(){
    int n, m;
    cin >> n >> m;
    vector<ll> a(n + 1);
    for(int i = 1; i <= n; i ++) cin >> a[i];
    ll lastpos = 0;
    ll now=0;
    ll sum = accumulate(a.begin() + 1, a.end(), 0ll);
    now=sum;
    ll cost = 0;
    vector<array<ll, 2>> que(m);
    for(auto &[pos, u] : que)
        cin >> pos >> u;
    for(auto &[pos, u] : que)
    {
        if(now<(pos-lastpos)){
            break;
        }
        now-=(pos-lastpos);
        cost=sum-now;
        now+=min(cost,a[u]);
        lastpos=pos;
    }
    cout << lastpos + now << '\n';
}

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    int n;
    cin >> n;
    while (n--)
        solve();
    return 0;
}