#include<bits/stdc++.h>

#define int long long
#define x first
#define y second
#define endl '\n'

using namespace std;

const int N=3e5+10,INF=1e14,mod=1e9+7,M=2e5+10;
const double eps = 1e-8;
typedef pair<int,int> PII;
typedef pair<PII,int> PIII;

int gcd(int a,int b){return b?gcd(b,a%b):a;}

int qmi(int a,int k){int res=1;while(k){if(k&1) res=res*a%mod;a=a*a%mod;k>>=1;}return res;}

int a[N],x[N],t[N],sh[N];
set<int> pos;
set<int> se[N];//他的下标 

void slove(){
	int n,m;cin>>n>>m;
	pos.clear();
	for(int i=1;i<=n;i++) se[i].clear();
	for(int i=1;i<=n;i++) cin>>a[i];
	for(int i=1;i<=m;i++){
		cin>>x[i]>>t[i];
		if(!se[t[i]].size()){
			sh[i]=a[t[i]],pos.insert(i); 
		}
		se[t[i]].insert(i);
	}
	pos.insert(m+1);
	for(int i=1;i<=n;i++){
		if (se[i].empty()) {
			sh[m+1]+=a[i];
		}
		se[i].insert(m+1);
	}
//	for(auto zz:pos) cout<<zz<<" "<<sh[zz]<<endl;
//	cout<<">>>"<<endl;
	for(int i=1;i<=m;i++){
		int dis=x[i]-x[i-1];
		vector<int> val;
//		cout<<dis<<endl;
//		for(auto zz:pos)cout<<zz<<" "<<sh[zz]<<endl;
		for(auto it=pos.begin();it!=pos.end();it++){
			auto zz=sh[*it];
			int nowp = *it;
			if(zz<dis)dis-=zz,sh[*it]=0,val.push_back(*it);
			else {
				sh[*it]-=dis;
				dis=0;
			}
		}
		if(dis>0){
			cout<<x[i]-dis<<endl;
			return ;
		}
		for(auto zz:val) pos.erase(zz);
		//然后就是补充t[i]
		val.clear();
		for(auto it=se[t[i]].begin();it!=se[t[i]].end();it++){
			//cout<<i<<" "<<t[i]<<" "<<*it<<endl;
			if(*it<=i)val.push_back(*it);
			else {
//				cout<<*it<<endl;
				pos.insert(*it);
				if(*it!=m+1)sh[*it]=a[t[i]];
				else sh[*it]+=a[t[i]];
				break; 
			}
		} 
		for(auto zz:val)se[t[i]].erase(zz);
	}
	cout<<x[m]+sh[m+1]<<endl;
}
/*
1
3 2
3 3 3
9 1
10 1
*/ 
signed main(){
	ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
	int T=1;cin>>T;
	while(T--) slove();
}