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