#include<bits/stdc++.h>
using namespace std;
#define MOD 1000000007
#define int long long
int t,j,n,m,sum,vis[100005],b1[100005],a[100005],b[100005],c[100005],a1[100005]; 
signed main(){
	cin>>t;
	while(t--){
		memset(vis,0,sizeof(vis));
		memset(b,0,sizeof(b));
		int could=0;
		sum=0;
		cin>>n>>m;
		for(int i=1;i<=n;i++){
			cin>>a[i];
			a1[i]=a[i];
		}
		for(int i=1;i<=m;i++){
			cin>>b1[i]>>c[i];
			b[i]=b1[i]-b[i-1];
			vis[c[i]]=i;
		}
		for(int i=1;i<=n;i++){
			if(vis[i]==0)could+=a[i];
		}
		for(int i=1;i<=m;i++){
//			a[c[i]]=a1[c[i]];
			j=i+1;
			if(a[c[i]]>=b[c[i]]){
				sum+=b[c[i]];
				b[c[i]]=0;
			}
			else{
				b[c[i]]-=a[c[i]];
				sum+=a[c[i]];
				a[c[i]]=0;
				while(j<=m&&b[c[i]]){
					if(b[c[i]]>=a[c[j]]){
						sum+=a[j];
						b[c[i]]-=a[c[j]];
						a[c[j]]=0;
						j++;
					}
					else{
						sum+=b[i];
						b[i]=0;
						a[j]-=b[i];
					}
				}
			}
			sum+=min(could,b[c[i]]);
			could-=min(could,b[c[i]]);
			if(could<=0&&j>m)break;
			a[c[i]]=a1[c[i]];
			if(vis[c[i]]==i)could+=a[c[i]];
		}
		cout<<sum+max(could,(int)0)<<endl;
	}
	return 0;
}