#include <cstring>
#include <stdio.h>
using namespace std;

#define MAXN 100000
char str[MAXN+5];

int main()
{
 //   freopen ("input.txt","r",stdin);
    int t, t1, k, k1;
    scanf ("%d", &t); getchar ();
    for (t1 = 1; t1 <= t; t1 ++)
    {
        memset (str, 0, sizeof(str));
        gets(str);
        scanf ("%d", &k); getchar ();
        printf ("Case #%d:\n", t1);
        int i, n = strlen(str), x = n/k, c = n%k, c1;
        for (k1 = 0; k1 < x; k1 ++)//  159263748
        {
            c1 = c, i = k1;
            while (c1 > 0 && i < n) {
                printf ("%c", str[i]);
                i += x+1;
                c1 --;
            }
            while (i < n) {
                printf ("%c", str[i]);
                i += x;
            }
        }
        for (i = x; c > 0; i += x+1) {
            printf ("%c", str[i]);
            c --;
        }
        putchar ('\n');
    }

    return 0;
}