#include<bits/stdc++.h>
using namespace std;
#define int long long
const int N=1e5+5;
int a[N],now[N],x[N],t[N];
int n,m;
deque<int> q[N];
void solve(){
	scanf("%lld%lld",&n,&m);
	for(int i=1;i<=n;++i)
		scanf("%lld",&a[i]),now[i]=a[i];
	for(int i=1;i<=m;++i)
		scanf("%lld%lld",&x[i],&t[i]);
	for(int i=1;i<=m;++i)
		q[t[i]].push_back(x[i]);
	for(int i=1;i<=n;++i)
		q[i].push_back(1e18);
	x[n+1]=1e18;
	set<pair<int, int> > s;
	for(int i=1;i<=n;++i)
		s.insert({q[i].front(),i});
	int pos=0,tp=1;
	int ans=0;
	while(!s.empty()){
		auto [v,u]=*s.begin();
		if(pos+now[u]>=x[tp]){
			now[u]-=x[tp]-pos;
			if(now[u]==0)
				s.erase(s.begin());
			pos=x[tp];
			now[t[tp]]=a[t[tp]];
			s.erase({x[tp],t[tp]});
			q[t[tp]].pop_front();
			s.insert({q[t[tp]].front(),t[tp]});
			tp++;
		}
		else{
			pos+=now[u];
			now[u]=0;
			s.erase(s.begin());
		}
		ans=max(ans,pos);
	}
	for(int i=1;i<=n;++i)
		q[i].clear();
	printf("%lld\n",ans);
}
signed main(){
	int T;cin>>T;
	while(T--)solve();
}