#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  cin >> n >> k;
  vector<bool> mark(n - k + 1);
  for (int i = 0; i < n - k + 1; i++) {
    string a;
    cin >> a;
    if (a == "YES") {
      mark[i] = true;
    } else {
      mark[i] = false;
    }
  }
  vector<string> answer(n);
  string name = "ABCDEFGH";
  int i = 0;
  do {
    string name_copy = name;
    name_copy.erase(name_copy.begin());
    transform(name_copy.begin(), name_copy.end(), name_copy.begin(), ::tolower);
    name_copy = name[0] + name_copy;
    answer[i] = name_copy;
    i = i + 1;
  } while (next_permutation(name.begin(), name.end()) && i < n);
  for (int i = 0; i < n - k + 1; i++) {
    if (!mark[i]) {
      answer[i + k - 1] = answer[i];
    }
  }
  for (int i = 0; i < n; i++) {
    cout << answer[i];
    if (i < n - 1) {
      cout << " ";
    } else {
      cout << endl;
    }
  }
  return 0;
}
