#include <iostream>
#include <string>
#include <map>
#include <vector>
#include <algorithm>
#include <cctype>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sstream>
#include <fstream>
#include <math.h>
#include <stack>
#include <queue>
#include <cstring>
#include <iostream>
using namespace std;

const int MAX = 522133279;
const double pi = 3.1415926535897;
const int mod = 1000000007;

char s[100000+100];
int n,T;
char res[100000 + 100];
int num[100000 + 100];

int main( )
{
    scanf("%d", &T );
    getchar( );
    for ( int cs = 1; cs <= T; cs++ )
    {
        gets( s );
        int len = strlen( s );
        scanf("%d", &n);
        getchar();

        int tmp = len % n;
        int line = (len + n - 1) / n;

        for ( int i = 0; i < n; i++ )
        {
            num[i] = ( (len/n) + (i < len%n) );
        }

        int index=0;
        res[len] = '\0';
        for ( int i = 0; i < n; i++ )
            for ( int j = 0; j < num[i]; j++ )
        {
            res[j * n + i] = s[index++];
        }

        printf("Case #%d:\n%s\n",cs, res );
    }

    return 0;
}