#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3fffffff;
const int mod = 1e9 + 7;
const int dx[4] = {1, -1, 0, 0};
const int dy[4] = {0, 0, 1, -1};
const double eps = 1e-8;
const int maxn = 1e5 + 7;
string ss[55];
string Other_catsworld[99] = {"Catsa", "Catsb", "Catsc", "Catsd", "Catse",
                              "Catsf", "Catsg", "Catsh", "Catsi", "Catsj"};
void init() {
  for (int i = 0; i < 55; i++) {
    ss[i] = "Catsworld";
  }
  for (int i = 10; i < 99; i++) {
    int a = i % 10;
    int b = i / 10;
    string temp = "";
    temp.append(1, b + 'a');
    temp.append(1, a + 'b');
    Other_catsworld[i] = "Cats" + temp;
  }
  return;
}
int main() {
  int n, k;
  while (cin >> n >> k) {
    init();
    int t = n - k + 1;
    int cnt = 0, flag = 0;
    string _s_;
    for (int i = 0; i < t; i++) {
      cin >> _s_;
      if (_s_ == "YES" && flag) {
        ss[i + k - 1] = Other_catsworld[cnt++];
      } else if (_s_ == "YES" && !flag) {
        flag = 1;
        for (int j = i + 1; j < i + k; j++) {
          ss[j] = Other_catsworld[cnt++];
        }
      } else {
        ss[i + k - 1] = ss[i];
      }
    }
    cout << ss[0];
    for (int i = 1; i < n; i++) {
      cout << " " << ss[i];
    }
    cout << endl;
  }
  return 0;
}
