// #pragma GCC optimize(1, 2, 3, "Ofast", "inline")
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned ll
#define int ll
#define ls p << 1
#define rs p << 1 | 1
#define lowbit(x) ((x) & (-x))
#define endl '\n'
#define ld long double

using PII = pair<int, int>;
#define MULTI_CASES
const int MaxN = 1e6 + 100;
const int INF = 1e9;
int T, N, M, K;
vector<int> a(MaxN);
inline void Solve() {
    cin >> N >> M;
    int ans = 0;
    for (int i = 1; i <= N; i++) {
        cin >> a[i];
        ans += a[i];
    }
    int last = 0;
    vector<PII> b(M + 1);
    for (int i = 1; i <= M; i++) {
        auto &[x, y] = b[i];
        cin >> x >> y;
        if (ans < x) break;
        int now = x - b[i - 1].first;
        if (now >= a[y]) {
            last += now - a[y];
            ans += a[y];
        } else {
            last += now;
            int p = min(last, a[y]);
            ans += p;
            last -= p;
        }
    }
    cout << ans << endl;
}
signed main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	srand(time(NULL));
#ifdef MULTI_CASES
	int T;
	cin >> T;
	while (T--)
#endif
		Solve();
}