#include <bits/stdc++.h>

using namespace std;

#define int long long

#define dbg(x) cout << #x << " = " << x << endl

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

    int sum = 0;
    vector<int> ve(n + 1);
    for (int i = 1; i <= n; i++) {
        cin >> ve[i];
        sum += ve[i];
    }

    struct Node {
        int a, b;
    };
    vector<Node> se(m + 1);
    se[0].a = 0, se[0].b = 0;
    for (int i = 1; i <= m; i++) {
        cin >> se[i].a >> se[i].b;
    }

    int aa = 0, ans = 0;
    for (int i = 1; i <= m; i++) {
        int x = se[i].a - se[i - 1].a;
        if ((sum - x) < 0) {
            cout << se[i - 1].a + sum << '\n';
            return;
        }

        sum -= x;
        ans += x;

        if (ans >= ve[se[i].b]) {
            sum += ve[se[i].b];
            ans -= ve[se[i].b];
        }
        else {
            sum += ans;
            ans = 0;
        }
    }
    // cout << sum << '\n';
    cout << se[se.size() - 1].a + sum << '\n';
}

signed main() {
    cin.tie(nullptr)->ios::sync_with_stdio(false);

    int T = 1; cin >> T;
    while (T--) solve();

    return 0;
}