#include <bits/stdc++.h>
using namespace std;
string str[52], ctr = "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
                ktr = "abcdefghijklmnopqrstuvwxyz";
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  for (int i = 0, j = 0; i < 52; ++i) {
    str[i] = "";
    if (i > 25)
      str[i] += 'A', str[i] += ktr[j++];
    else
      str[i] += ctr[i];
  }
  string ans[60];
  vector<string> vec;
  int n, k, idx = 0;
  cin >> n >> k;
  for (int i = 0; i < n - k + 1; ++i) {
    string ptr;
    cin >> ptr;
    vec.push_back(ptr);
  }
  for (int i = 0; i < (int)vec.size(); ++i) {
    if (vec[i] == "YES") {
      for (int j = 0; j < i + k; ++j) {
        if (!(int)ans[j].size()) ans[j] = str[idx++];
      }
    } else {
      if (i)
        ans[i + k - 1] = ans[i];
      else {
        for (int j = 0; j < i + k; ++j) {
          if (!j)
            ans[j] = str[idx++];
          else if (j == 1)
            ans[j] = ans[j - 1];
          else
            ans[j] = str[idx++];
        }
      }
    }
  }
  for (int i = 0; i < n; ++i) cout << ans[i] << " ";
  cout << "\n";
  cin.clear();
  cin.ignore();
  cin.get();
  return 0;
}
