#include<bits/stdc++.h>
using namespace std;
#define int long long
#define ull unsigned long long
#define endl "\n"

using namespace std;
const int N = 1e5+5;
pair<int, int>op[N];
int a[N];
signed main(void)
{
	ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	int t;
	cin >> t;
	while (t--)
	{
		int n, m;
		cin >> n >> m;
		int sumnow = 0;
		for (int i = 1; i <= n; i++)
		{
			cin >> a[i];
			sumnow += a[i];
		}
		for (int i = 1; i <= m; i++)
		{
			cin >> op[i].first >> op[i].second;
		}
		int now = 0;
		int havenow = 0;
		int anw = 0;
		for (int i = 1; i <= m; i++)
		{
			int cango = sumnow - havenow;
			if (cango < op[i].first - op[i - 1].first)
			{
				anw += cango;
				break;
			}
			else
			{
				havenow += op[i].first - op[i - 1].first;
				if (a[op[i].second] >= havenow)
				{
					havenow = 0;
				}
				else
				{
					havenow -= a[op[i].second];
				}
				anw += op[i].first - op[i - 1].first;
			}
		}
		anw += sumnow - havenow;
		cout << anw << endl;
	}
	return 0;
}