#include <bits/stdc++.h>
using ll = long long;
using ull = unsigned long long;
using vi = std::vector<int>;
using vll = std::vector<ll>;
using vull = std::vector<ull>;
using namespace std;
string generate_name(int i) {
  return string(1, char('A' + i / 26)) + string(1, char('a' + (i) % 26));
}
int main() {
  ios_base::sync_with_stdio(false);
  int N, K;
  cin >> N >> K;
  vector<bool> repeat(N, false);
  for (int i = K - 1; i < N; ++i) {
    string in;
    cin >> in;
    repeat[i] = (in == "NO");
  }
  vector<string> names(N);
  for (int i = 0; i < N; ++i) {
    names[i] = generate_name(i + 2);
  }
  for (int i = 0; i < N; ++i) {
    if (repeat[i]) {
      names[i] = names[i - K + 1];
    }
  }
  for (int i = 0; i < N; ++i) {
    cout << names[i] << " ";
  }
  cout << endl;
}
