#include<bits/stdc++.h>
typedef long long ll;
const long long mod = 4294967296;
#define INF 0x7fffffff //32位最大值
//#define INF 0x3f3f3f3f3f3f3f3f longlong最大值
#define maxn 1000000+10
using namespace std;
struct cha
{
    int price;
    int number;
} c[27];
int cmp(cha a,cha b)
{
    return a.price<b.price;
}
int main()
{
    //freopen("C:\\Users\\Weicheng\\Desktop\\in.txt","r",stdin);
    int t,n;
    scanf("%d",&t);
    int sum=0;
    while(t--)
    {
        ll ans=0,flag=0,ans1=0;
        scanf("%d",&n);
        for(int i=0; i<n; i++)
        {
            scanf("%d%d",&c[i].price,&c[i].number);
            if(c[i].price<0)
                flag+=c[i].number;
            sum+=c[i].number;
        }
        int k=1;
        sort(c,c+n,cmp);
        if(flag==0)
        {
            for(int i=0; i<n; i++)
            {
                while(c[i].number)
                {
                    ans+=k*c[i].price;
                    c[i].number--;
                    k++;
                }
            }

        }

        else
        {
            ans=0;
            int jj=0;
            //cout<<flag<<endl;
            for(int j=0; j<=flag; j++)
            {
                k=1;
                jj=flag-j;
                ans1=0;
                //cout<<"跳过数的数量:"<<jj<<endl;
                for(int i=0; i<n; i++)
                {
                    int kk=c[i].number;
                   // cout<<"kk:"<<kk<<endl;
                    while(kk)
                    {
                        kk--;
                        if(jj==0)
                        {
                            //cout<<"ans1："<<ans1<<endl;
                            ans1+=k*c[i].price;
                            k++;
                            //cout<<"k:"<<k<<endl;
                        }
                        else
                            jj--;

                    }


                }
               // cout<<"ans1:"<<ans1<<endl;
                //cout<<"ans:"<<ans<<endl;
                ans=max(ans,ans1);

            }
        }

        cout<<ans<<endl;
    }
    return 0;
}