#include<bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'
const int N=1e6+10,mod=998244353;
typedef pair<int,int>PII;
typedef pair<double,double>PDD;
int n,m,k;
int a[N];
PII b[N];
int s[N];
void solve() {
    cin>>n>>m;
    int sum=0;
    for(int i=1;i<=n;i++) {
        cin>>a[i];
        sum+=a[i];
    }
    for(int i=1;i<=m;i++) {
        cin>>b[i].first>>b[i].second;
    }
    if(b[1].first>sum) {
        cout<<sum<<endl;
        return;
    }
    int pos=0;
    map<int,int>mp;
    int qk=0;
    int ans=0;
    bool f=true;
    for(int i=1;i<=m;i++) {
        int len=b[i].first-b[i-1].first;
        if(len>=a[b[i].second]) {
            if(qk+len>sum) {
                ans=b[i].first+sum-qk;
                f=false;
                break;
            }
            qk+=len-a[b[i].second];
        }
        else {
            qk-=a[b[i].second]-len;
            qk=max(0LL,qk);
        }
    }
    //cout<<qk<<endl;
    if(f)ans=b[m].first+sum-qk;
    cout<<ans<<endl;
}
signed main() {
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    int T=1;
    cin>>T;
    while(T--) {
        solve();
    }
    return 0;
}