#include<cstdio>
const int N=1000001,D=8;
int ciur[N],p[N];//nrmax[N];
void prec(){
    int i,j,k=0;
    p[0]=1;
    for(i=2;i*i<=N;i++)
        if(!ciur[i]){
            p[k+1]=p[k]*i;
            k++;
            for(j=i;j<N;j+=i)
                ciur[j]++;
        }
}
/*void maxs(){
    for(i=1;i<N;i++){
        sd[d[i]][i] = 1;
        for(int j=0 ; j<D ; j++)
            sd[j][i] += sd[j][i-1];
    }
}*/
int main(){
    int k,t,i,j,n;
    freopen("divprim.in","r",stdin);
    freopen("divprim.out","w",stdout);
    prec();
   // maxs();
    scanf("%d",&t);
    for(i=1;i<=t;i++){
        scanf("%d%d",&n,&k);
        if(k>=D || p[k]>n)
            printf("0\n");
        else
            for(j=n;j>=1;j--)
                if(ciur[j]==k){
                    printf("%d\n",j);
                    break;
                }
    }
    return 0;
}