#include<iostream>
#include<cstdio>
#include<fstream>
#include<cstring>
#include<algorithm>
#include<cstdlib>
using namespace std;

struct item
{
   int v;
   int t;
};

int T,N;
item b[35];

bool mycmp(item x,item y)
{
    return x.v>y.v;
}

void solve()
{
   scanf("%d",&T);
   while(T--)
   {
        scanf("%d",&N);
        for(int i=1;i<=N;i++)
           scanf("%d%d",&b[i].v,&b[i].t);
        sort(b+1,b+N+1,mycmp);
        int best=0,prev=0;
        int ans=0,len=0;
        for(int i=1;i<=N;i++)
           for(int j=1;j<=b[i].t;j++)
           {
                ans=ans+b[i].v+prev;
                prev+=b[i].v;
                len++;
                if(ans>best)best=ans;
           }
        printf("%d\n",best);
   }
}

int main()
{
    solve();
    return 0;
}