#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N = 1e5+9;
int n,m,s,k;
struct{
	int s,i;	
}b[N];
int a[N],x[N];
void solve() {
	int sum = 0;
	cin>>n>>m;
	for(int i = 1;i <= n;i++){
		cin>>a[i];
		sum+=a[i];
		x[i]=a[i];
	}
	for(int i = 1;i <= m;i++){
		cin>>b[i].s>>b[i].i;
	}
	int l = 1, r = 1, now = 0;
	for(int i = 1;i <= m;i++){
//		while(r<=m&&now+sum>=b[r].s)
//			r++;
		int d = b[i].s-now;
		for(l=max(l,i);d>0&&l<=m;l++)
		{
			if(d<=a[b[l].i]){
				sum-=d;
				a[b[l].i]-=d;
				d=0;
				break;
			}
			sum-=a[b[l].i];
			d-=a[b[l].i];
			a[b[l].i]=0;
		}
		if(d>a[b[i].i])
			sum=sum+x[b[i].i]-d;
		else
			sum=sum+x[b[i].i]-a[b[i].i];
		a[b[i].i]=x[b[i].i];
		now=b[i].s;
	}
	now+=sum;
	cout<<now<<"\n";
}

signed main(){
	std::ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
	int _=1;	cin>>_;
	while(_--)
		solve();
	return 0;
}