#include<bits/stdc++.h>
#define int long long
#define endl '\n'
using namespace std;
void solve()
{
    int n,m,sum=0,cost=0,ans=0;
    cin>>n>>m;
    vector<int> a(n+1),w(m+1),t(m+1);
    for(int i=1;i<=n;i++) cin>>a[i],sum+=a[i];
    for(int i=1;i<=m;i++) cin>>w[i]>>t[i];
    int pos;
    for(int i=1;i<=m;i++)
    {
        cost+=w[i]-w[i-1];
        if(sum<cost) {pos=i;break;}
        if(cost>a[t[i]]) cost-=a[t[i]];
        else cost=0;
        ans+=w[i]-w[i-1];
    }
    if(cost>sum)
        cost-=w[pos]-w[pos-1];
    ans+=sum-cost;
    cout<<ans<<endl;
}
signed main()
{
    cin.tie(0)->sync_with_stdio(0);
    int t=1;
    cin>>t;
    while(t--) solve();
    return 0;
}