#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, cnt = 0, in;
  string s[100], now = "abcde", jwb[100] = {};
  cin >> n >> k;
  for (int i = 1; i <= n - k + 1; ++i) {
    cin >> s[i];
    if (s[i][0] == 'Y') {
      ++cnt;
      in = i;
    }
  }
  if (cnt) {
    for (int i = in; i <= in + k - 1; ++i) {
      jwb[i] = now;
      next_permutation(now.begin(), now.end());
    }
    for (int i = in + k; i <= n; ++i) {
      if (s[i - k + 1][0] == 'Y') {
        jwb[i] = now;
        next_permutation(now.begin(), now.end());
      } else {
        jwb[i] = jwb[i - k + 1];
      }
    }
    for (int i = in - 1; i; --i) {
      if (s[i][0] == 'Y') {
        jwb[i] = now;
        next_permutation(now.begin(), now.end());
      } else {
        jwb[i] = jwb[i + k - 1];
      }
    }
  } else {
    for (int i = 1; i <= n; ++i) jwb[i] = 'a';
  }
  for (int i = 1; i <= n; ++i) {
    jwb[i][0] += 'A' - 'a';
    cout << jwb[i] << ' ';
  }
  cout << endl;
  return 0;
}
