#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 sum = accumulate(a.begin() + 1, a.end(), 0ll);
    ll cost = 0;
    for (int i = 1; i <= m; i++) {
        int pos, u;
        cin >> pos >> u;
        cost += pos - lastpos;
        if (sum < cost)
            break;
        sum = sum - (pos - lastpos) + min(cost, a[u]);
        cost -= min(cost, a[u]);
        lastpos = pos;
    }
    cout << lastpos + sum << '\n';
}

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