/*
* this code is made by crazyacking
* Verdict: Accepted
* Submission Date: 2015-05-23-13.06
* Time: 0MS
* Memory: 137KB
*/
#include <queue>
#include <cstdio>
#include <set>
#include <string>
#include <stack>
#include <cmath>
#include <climits>
#include <map>
#include <cstdlib>
#include <iostream>
#include <vector>
#include <algorithm>
#include <cstring>
#define  LL long long
#define  ULL unsigned long long
using namespace std;
const int MAXN=100010;
char s[MAXN];
int cha[MAXN];
int main()
{
        int t,Cas=1;
        scanf("%d",&t);
        getchar();
        while(t--)
        {
                gets(s);
                int n;
                scanf("%d",&n);
                getchar();
                printf("Case #%d:\n",Cas++);
                int len=strlen(s);
                int line;
                if(len%n==0) line=len/n;
                else line=len/n+1;
                int m=len%n;
                memset(cha,0,sizeof cha);
                int cnt=1;
                if(m!=0)
                {
                        for(int i=m+1;i<n;++i)
                                cha[i]=cnt++;
                }
                for(int i=0;i<line;++i)
                {
                        if(len%n!=0 && i==line-1)
                        {
                                int sta=i;
                                for(int j=0;j<m;++j)
                                {
                                        printf("%c",s[sta]);
                                        sta+=line;
                                }


                        }
                        else
                        {
                                int sta=i;
                                for(int j=0;j<n;++j)
                                {
                                        printf("%c",s[sta-cha[j]]);
                                        sta+=line;
                                }
                        }
                }
                puts("");
        }
        return 0;
}
/*

*/