#include <fstream>
using namespace std;
ifstream cin ("divprim.in");
ofstream cout ("divprim.out");
char ciur[1000050];
int main()
{
    int i,j,t,nr,k;
    ciur[0]=ciur[1]=0;
    for (i=2; i*i<=1000010; i++)
        if (ciur[i]==0)
            for (j=i; j<=1000010; j=j+i)
                ciur[j]++;
    cin>>t;
    for (i=1; i<=t; i++)
    {
        cin>>nr>>k;
        while (ciur[nr]!=k && nr>0)
            nr--;
        if (nr==0)
            cout<<0<<"\n";
        else
            cout<<nr<<"\n";
    }
    return 0;
}