#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, k;
  cin >> n >> k;
  vector<string> notes, names(55);
  for (int i = 0; i <= n - k; i++) {
    string m;
    cin >> m;
    notes.push_back(m);
  }
  for (int i = 0; i < 26; i++) {
    names[i] = (i + 'A');
  }
  if (n >= 26) {
    for (int i = 26; i <= n; i++) {
      names[i] = names[i - 26] + 'a';
    }
  }
  for (int i = 0; i <= n - k; i++) {
    if (notes[i] == "NO") names[i + k - 1] = names[i];
  }
  for (int i = 0; i < n; i++) {
    cout << names[i] << " ";
  }
  return 0;
}
