#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <algorithm>
#include <stack>
#include <cmath>
using namespace std;
char s[110000]; int len;
int n, divd, mod;
int main (){
    int i, j, k, T, ii;
    int Ti;
    scanf ( "%d", &T );
    Ti = 0;
    while ( T -- ){
        getchar ();
        gets (s);
        len = strlen (s);
        scanf ( "%d", &n );
        divd = len / n;
        mod = len % n;
        printf ( "Case #%d:\n", ++Ti );
        for ( i = 0; i < divd; i ++ ){
            ii = i;
            j = 1;
            while ( ii < len ){
                printf ( "%c", s[ii] );
                if ( j <= mod ) ii += divd+1;
                else ii += divd;
                j ++;
            }
        }
        for ( i = 0; i < mod; i ++ ){
            printf ( "%c", s[i*(divd+1)+divd] );
        }
        printf ( "\n" );
    }
    return 0;
}