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

using i64 = long long;

void solve() {
    int n, m;
    cin >> n >> m;

    vector<i64> a(n), b(m + 1, 0);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
        b[0] += a[i];
    }

    vector<int> x(m + 1), t(m + 1), free(m + 1, 0);
    for (int i = 1; i <= m; i++) {
        cin >> x[i] >> t[i];
        t[i]--;
    }

    i64 ans = 0;
    for (int i = 1; i <= m; i++) {
        i64 cost = x[i] - x[i - 1];
        if (b[i - 1] < cost) {
            ans = x[i - 1] + cost;
            break;
        } else {
            i64 cal = cost + free[i - 1], can = a[t[i]];
            if (cal >= can) {
                b[i] = b[i - 1] - cost + can;
                free[i] = cal - can;
            } else {
                b[i] = b[i - 1] - cost + cal;
                free[i] = 0;
            }

            if (i == m) {
                ans = x[i] + b[i];
            }
        }
    }

    cout << ans << endl;
}

int main(void)
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t;
    cin >> t;
    while (t--) {
        solve();
    }

    return 0;
}