#include <cstdio>

using namespace std;
int c[1000005];
int main()
{
    freopen("divprim.in","r",stdin);
    freopen("divprim.out","w",stdout);
    int m,n,i,j,k;
    scanf("%d",&m);
    for(i=2; i<=1000000; i+=2)
        c[i]++;
    for(i=3; i<=1000000; i+=2)
        if(!c[i])
        for(j=i; j<=1000000; j+=i)
            c[j]++;
    for(j=1; j<=m; j++)
    {
        scanf("%d%d",&n,&k);
        for(i=n; i>=1; i--)
            if(c[i]==k)
                break;
        printf("%d\n",i);
    }
    return 0;
}