#include <iostream>
#include <fstream>
#define LN 1000000
using namespace std;
ifstream in("divprim.in");
ofstream out("divprim.out");

int t,k,n;
int nrdiv[LN+2];

void preprocDiv()
{
    for(int i=2;i<=LN;++i)
    {
        if(nrdiv[i]==0)
        {
            for(int j=i;j<=LN;j+=i)
                nrdiv[j]++;
        }
    }
}

/*int bs(int st,int dr)
{
    if(st>dr)
        return 0;
    else{
        int mij=st+(dr-st)/2;

    }
}*/

int main()
{
    preprocDiv();
    /*for(int i=1;i<=LN;++i)
        out<<i<<" ";
    out<<"\n";
    for(int i=1;i<=LN;++i)
        out<<nrdiv[i]<<" ";*/
    in>>t;
    for(int q=1;q<=t;++q)
    {
        in>>n>>k;
        int sol=n-1;
        while(nrdiv[sol]!=k && sol>0)
            sol--;
        out<<sol<<"\n";
    }

    return 0;
}