#include<cmath>
#include<cstring>
#include<cstdlib>
#include<iostream>
#include<set>
#include<vector>
#include<string>
#include<cstring>
#include<algorithm>
using namespace std;
int a[100000];
int n,x,y;
int step;
int ans,sum;
int T;
int sstep;
int main() {
    cin>>T;
    for(int m=1;m<=T;m++){
    sum=0;
    cin>>n;
    step=1;
    ans=0;
    for(int i=1;i<=n;i++) {
        cin>>x>>y;
        for(int j=1;j<=y;j++) {
            a[step]=x;
            step++;
        }
    }
    sort(a+1,a+step);
    for(int i=step-1;i>=1;i--) {
        if (a[i]<=0) {
            if ( sum > -a[i] )    {
                sum+=a[i];
                ans+=sum;
            }
            else break;
        }
        else {
            sum+=a[i];
            ans+=sum;
        }
    }
    cout<<ans<<endl;}
}