#include <bits/stdc++.h>

using namespace std;
int T,k,N;
bitset <1000005> V;
pair <int,int> Prim[1000005],Nrk[8];
bool Compare(const pair<int,int> &a,const pair<int,int> &b)
{
    if(a.second==b.second)
        return a.first<b.first;
    return a.second<b.second;
}
int main()
{
    ifstream f("divprim.in");
    ofstream g("divprim.out");
    for(int i=1; i<=1000000; i++)
        Prim[i].first=i;
    for(int i=2; i<=1000000; (i==2?i++:i+=2))
        if(!V[i])
            for(int j=1; i*j<=1000000; j++)
                V[i*j]=true,Prim[i*j].second++;
    sort(Prim+1,Prim+1000001,Compare);
    int x=0,y=1,cnt=0;
    for(int i=1;i<=1000000;i++)
       if(cnt!=Prim[i].second)
        Nrk[cnt].first=y,Nrk[cnt].second=i-1,y=i,cnt++;
    Nrk[cnt].first=y,Nrk[cnt].second=1000000;
    f>>T;
    while(T--)
    {
       f>>N>>k;
       int st=Nrk[k].first,dr=Nrk[k].second,ans=0;
       while(st<=dr)
       {
           int mi=(st+dr)>>1;
           if(Prim[mi].first<=N)
            ans=Prim[mi].first,st=mi+1;
           else dr=mi-1;
       }
       g<<ans<<'\n';
    }
    return 0;
}