#include <iostream>
#include <cstring>
#include <string>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <cstdlib>
#include <stack>
#include <map>
#include <vector>
using namespace std;

#define LL long long
#define N 100020
#define M 2020
#define eps 1e-10
#define inf 1e10
#define Pi acos(-1.0)
#pragma comment(linker, "/STACK:1024000000,1024000000")

vector<char> v[N];
char s[N];
int main(){
    int cas, kk = 0;
    scanf("%d", &cas);
    getchar();
    while(cas--){
        printf("Case #%d:\n", ++kk);
        gets(s);
        int k;
        scanf("%d", &k);
        getchar();
        int n = strlen(s), cnt = 0;
        while(n > 0){
          //  cout << n << endl;
            int tmp = (n + k - 1) / k;
            for(int i = 0; i < tmp; ++i)
                v[i].push_back(s[cnt++]);
            n -= tmp, k--;
        }
        for(int i = 0; i < N; ++i){
            int m = v[i].size();
            if(m == 0) break;
            for(int j = 0; j < m; ++j)
                putchar(v[i][j]);
            v[i].clear();
        }
        puts("");
    }
    return 0;
}