#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define pb push_back
void solve() {
	ll sum = 0;
	ll n, m;
	cin >> n >> m;
	std::vector<ll> v(n + 1);
	for (int i = 1; i <= n; i++) {
		cin >> v[i];
		sum += v[i];
	}
	std::vector<array<ll, 2>> c(m + 1);
	for (int i = 1; i <= m; i++) {
		cin >> c[i][0] >> c[i][1];
	}
	ll pre = 0;
	ll qq = 0;
	for (int i = 1; i <= m; i++) {
		ll d = c[i][0] - pre;
		ll aim = d + c[i - 1][0];
		if (d + qq > sum) {
			cout << c[i - 1][0] + (sum - qq) << "\n";
			return;
		}
		qq += d;
		ll f = min(v[c[i][1]], qq);
		qq -= f;
		pre = c[i][0];
	}
	cout << c[m][0] + (sum - qq) << "\n";
}
int main() {
	ios::sync_with_stdio(false); cin.tie(0);
	int t = 1;
	cin >> t;
	while (t--)solve();
}