#include <bits/stdc++.h>

using namespace std;

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

int a[1000005], nr_div[1000005];

int main()
{
    int n, i, j, q, k, exista;
    n = 1000000;
    a[2] = 1;
    for(i = 3; i <= n; i+=2)
        a[i] = 1;
    for(i = 3; i * i <= n; i+=2)
        if(a[i] == 1)
            for(j = i * i; j <= n; j+= 2 * i)
                a[j] = 0;
    for(i = 2; i <= n; i++)
        if(a[i] == 1)
            for(j = i; j <= n; j+=i)
                nr_div[j]++;
    fin >> q;
    for(i = 1; i <= q; i++)
    {
        fin >> n >> k;
        exista = 0;
        for(j = n; j >= 1; j--)
            if(nr_div[j] == k)
            {
                fout << j << "\n";
                exista = 1;
                break;
            }
        if(exista == 0)
            fout << 0 << "\n";
    }
    return 0;
}