#pragma GCC optimize(3, "Ofast", "inline")
#define FOR(i, a, b) for(int i = (a); i <= (b); i ++)
#define ROF(i, a, b) for(int i = (a); i >= (b); i --)
#define debug(x) cerr << (#x) << ": " << (x) << '\n'
#define pb push_back
#define IOS ios::sync_with_stdio(0), cin.tie(0), cout.tie(0)
 
#include <bits/stdc++.h>
 
using namespace std;
 
// #define int long long
typedef long long ll;
typedef unsigned long long ull;
typedef array<int, 2> pii;
typedef array<ll, 2> pll;
mt19937_64 rnd(chrono::steady_clock::now().time_since_epoch().count());

int n, m;
int a[100010];
int x[100010], t[100010];
int d[100010];

void solve(int T) {
	cin >> n >> m;
	FOR(i, 1, n) cin >> a[i];
	FOR(i, 1, m) cin >> x[i] >> t[i];
	FOR(i, 1, m) d[i] = x[i] - x[i - 1];
	int tot = 0;
	FOR(i, 1, n) tot += a[i];
	int now = tot;
	FOR(i, 1, m) {
		now -= d[i];
		if(now < 0) {
			cout << x[i] + now << '\n';
			return;
		}
		now += min(tot - now, a[t[i]]);
	}
	cout << x[m] + now << '\n';
}

void init() {

}

signed main() {
	IOS;
	int t = 1;
	cin >> t;
	init();
	FOR(T, 1, t) {
		solve(T);
	}
  	return 0;
}