#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
struct node{
    int x,y;
}a[1000]
;
bool cmp(node a,node b){
    return a.x>b.x;
}
int main()
{
    int t;
    scanf("%d",&t);
    while(t--){
        int n;
        scanf("%d",&n);
        for(int i=1;i<=n;i++){
            int x,y;
            scanf("%d%d",&x,&y);
            a[i].x=x,a[i].y=y;
        }
        sort(a+1,a+1+n,cmp);
        int ans=0;
        int step=0;
        int sum=0;
        for(int i=1;i<=n;i++){
            for(int j=1;j<=a[i].y;j++){
                step=step+sum+a[i].x;
                sum+=a[i].x;
            //    printf("--%d\n",step);
                if(step>=ans){
                    ans=step;
                }
                else break;
            }
            if(step<ans)break;
        }
        printf("%d\n",ans);
    }
    return 0;
}