#include <bits/stdc++.h>
#define int long long
#define endl '\n'
using namespace std;
using i64 = long long;
const int inf = 1e18;
void solve()
{
    int n, k;
    cin >> n >> k;
    int sum = 0;
    vector<int> val(n + 1, 0);
    vector<pair<int, int>> b(k + 10, {0, 0});
    for (int i = 1; i <= n; i++)
    {
        cin >> val[i];
        sum += val[i];
    }
    for (int i = 1; i <= k; i++)
    {
        cin >> b[i].first >> b[i].second;
    }
    b[k + 1] = {1e18, 0};
    int ans = 0;
    int now = 0;
    for (int i = 1; i <= k + 1; i++)
    {
        now += b[i].first - b[i - 1].first;
        if (now > sum)
        {
            ans += sum - (now - (b[i].first - b[i - 1].first));
            break;
        }
        else
        {
            // cout << b[i].first - b[i - 1].first << ' ';
            ans += b[i].first - b[i - 1].first;
            now = max((int)0, now - val[b[i].second]);
        }
    }
    cout << ans << endl;
}

signed main()
{
    ios::sync_with_stdio(false), cin.tie(0);
    int T = 1;
    cin >> T;
    while (T--)
        solve();
    // system("pause");
    return 0;
}