/**
 *Author: xiaoran
 *Time: 2012?5?23 22:21
 ******************
 *Solution:
 *
 */

#include<iostream>
#include<string>
#include<cstring>
#include<cstdio>
using namespace std;
string s;
char ss[100005];
int main()
{
    int i=0,n,k,t,c,r,kk;
    cin>>t;
    while(i<t){
        getchar();
        gets(ss);
        //getchar();
        cin>>c;
        int len=strlen(ss);
        n=len%c;
        r=len/c+(n>0?1:0);
        k=0; kk=0;
        cout<<"Case #"<<++i<<":"<<endl;
        while(k<r){
            int j=0,jj;
            jj=k;
            while(j<n){
                if(jj<len){
                    kk++;
                    cout<<ss[jj];
                    jj+=r;
                }
                ++j;
                //cout<<jj<<endl;
            }
            if(kk==len) break;
            //if(k==r) break;
            while(jj<len){
                kk++;
                if(jj<len) cout<<ss[jj];
                jj+=r-(n>0?1:0);

                //cout<<jj<<endl;
            }
            ++k;
        }
        cout<<endl;
    }
    return 0;
}