#include <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
#define T 100 + 5
#define N 100000 + 5

int _, len, K[T];
char s[T][N];

int main()
{
    scanf("%d\n", &_);
    for (int i = 1; i <= _; i ++)
    {
        gets(s[i] + 1);
        if (i < _)
            scanf("%d\n", K + i);
        else scanf("%d", K + i);
    }
    for (int t = 1; t <= _; t ++)
    {
        int len = strlen(s[t] + 1), k = K[t];
        int r = (len + k - 1) / k, lim = (len - 1) % k + 1;
        printf("Case #%d:\n", t);
        for (int i = 1; i <= r; i ++)
            for (int j = 1; (i - 1) * k + j <= len && j <= k; j ++)
                printf("%c", s[t][(j - 1) * r + i - max(0, j - 1 - lim)]);
        putchar('\n');
    }
    return 0;
}