#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>#include <algorithm>#include <cmath>#include <string>#include <vector>#include <queue>#include <set>#include <map>#include <ctime>#define inf 0x3f3f3f3f#define Inf 0x3FFFFFFFFFFFFFFFLLusing namespace std;int lens[2200];int main() { int n, k; string s; int ca = 1; bool begin = true; while (cin >> n >> k) { if (n == 0 && k == 0) break; for (int i = 0; i < n; ++i) { cin >> s; lens[i] = s.length(); } sort(lens, lens + n); int t = n / k; bool flag = true; for (int i = 0; i < t; ++i) { for (int j = 0; j < k - 1; ++j) { int a = i * k + j; if (lens[a + 1] - lens[a] > 2) { flag = false; break; } } if (!flag) break; } if (!begin) { cout << endl; } begin = false; cout << "Case " << ca++ << ": "; if (flag) cout << "yes" << endl; else cout << "no" << endl; } return 0;}
