#include <bits/stdc++.h>

using namespace std;

ifstream fin("divprim.in");
ofstream fout("divprim.out");

int n,a[1500005],b[1500005];

int main()
{
    int k,t,i,j;
    n=1000000;
    a[0]=1;
    a[1]=1;
    for(i=4;i<=n;i+=2)
        a[i]=1;
    for(i=3;i*i<=n;i+=2)
        if(a[i]==0)
            for(j=i*i;j<=n;j+=2*i)
                a[j]=1;
    for(i=2;i<=n;i+=2)
        b[i]++;
    for(i=3;i<=n;i+=2)
        if(a[i]==0)
            for(j=i;j<=n;j+=i)
                b[j]++;
    fin>>t;
    for(i=1;i<=t;i++)
    {
        fin>>n>>k;
        for(j=n;b[j]!=k && j>0;j--)
            ;
        fout<<j<<"\n";
    }
    return 0;
}