#include<cstdio>
#include<algorithm>
#include<cstring>
#define Nmax 1000005
using namespace std;
int n,k,i,j,t,pr[Nmax],p;
int w[Nmax];
int v[8][380005];
int cb(int k,int x)
{
    int st=1,dr=v[k][0],mij=0;
    if (x<v[k][1]) return 0;
    while (st<=dr)
    {
        mij=(st+dr)/2;
        if (v[k][mij]<=x && v[k][mij+1]>x) return mij;
        if (v[k][mij]<x) st=mij+1;
        else dr=mij-1;
    }
    return 0;
}
void numereprime()
{
    long long i,j;
    for (i=2;i<=Nmax-5;i++)
    if (!w[i])
    {
        w[i]=1;
        for (j=i+i;j<=Nmax-5;j+=i)
        ++w[j];
    }
}
int main()
{
    freopen("divprim.in","r",stdin);
    freopen("divprim.out","w",stdout);
    numereprime();
    for (i=2;i<=1000000;i++)
    v[w[i]][++v[w[i]][0]]=i;
    scanf("%d",&t);
    while (t--)
    {
        scanf("%d %d",&n,&k);
        p=cb(k,n);
        if (p==0)
        {printf("0\n"); continue;}
        printf("%d\n",v[k][p]);
    }
    return 0;
}