#include <cstdio>

using namespace std;
int v[1000005],t,n,i,j,dr,k,ok;
int main()
{
    freopen("divprim.in","r",stdin);
    freopen("divprim.out","w",stdout);
    for(i=2;i<=1000;i++)
        if(v[i]==0)
    {
        v[i]=1;
        for(j=2*i;j<=1000000;j+=i)
        v[j]++;

    }
    scanf("%d",&t);
    for(j=1;j<=t;j++)
    {

        scanf("%d%d",&n,&k);
        ok=0;

        for(i=n;i>=1;i--)
        if(v[i]==k)
        {
            ok=1;
            printf("%d\n",i);
            break;
        }
    if(ok==0)
        printf("%d\n",0);
    }
    return 0;
}