# include <stdio.h>
# include <string.h>
# include <iostream>
using namespace std; 
const int Max = 100001;
char str[Max];
int main() 
{
    int N, n, i, j, k, count, len, remainder, index, shang, remainder_1;
    scanf("%d", &N);
    k = 1;
    while(N--){
        getchar();
        gets(str);
        scanf("%d", &n);
        len = strlen(str);
        shang = len / n;
        remainder = len % n;
        //大循环是行数 
        count = 0;
        printf("Case #%d:\n", k++);
        for(i = 0; i < (remainder > 0 ? (shang+1) : shang); i++){
            index = i;
            remainder_1 = remainder;
            for(j = 0; j < n; j++){
                if(count >= len) break;
                printf("%c", str[index]);
                count++;
                if(remainder_1 > 0){
                    index += shang + 1;
                    remainder_1--;
                }else
                    index += shang;
            }
        }
        
        printf("\n");
    }
    return 0;
}