/**
*  Author: Aliemo
*  Data:
*  Problem:
*  Time: O()
*/
#include <cstdio>
#include <iostream>
#include <string>
#include <cstring>
#include <cmath>
#include <algorithm>

#define int long long
#define rr register

#define inf 1e9
#define MAXN 200010
#define MAXM 510

#define lson rt << 1
#define rson rt << 1 | 1

using namespace std;

inline int read() {
	int s = 0, f = 0;
	char ch = getchar();
	while (!isdigit(ch)) f |= ch == '-', ch = getchar();
	while (isdigit(ch)) s = s * 10 + (ch ^ 48), ch = getchar();
	return f ? -s : s;
}

void print(int x) {
	if (x < 0) putchar('-'), x = -x;
	if (x > 9) print(x / 10);
	putchar(x % 10 + 48);
}

int T, n, m, ans, res, cnt;

int a[MAXN], x[MAXN], y[MAXN];

signed main() {
	T = read();
	while (T--) {
		n = read(), m = read();
		res = 0;
		for (int i = 1; i <= n; i++) {
			a[i] = read();
			res += a[i];
		}
		ans = res;cnt = 0;
		for (int i = 1; i <= m; i++) {
			x[i] = read(), y[i] = read();
			int temp = max(x[i] - a[y[i]], x[i] - x[i - 1]);
			// cout << te
			if (res >= x[i]) {
				res -= temp;
				res += min(temp, a[y[i]]);
				cnt = x[i];
				ans = max(cnt + res, ans);
			}
		}
		ans = max(ans, cnt + res);
		cout << ans << "\n";
	}
}

/*

1
1 1
1000000000
1000000000 1

*/