#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, c = 50;
  string arra[104], kelma;
  cin >> n >> k;
  vector<string> ans;
  for (int i = 0; i < 26; i++) {
    arra[i] = 'A';
    arra[i] += ('a' + i);
  }
  for (int i = 26; i < (26 * 2); i++) {
    arra[i] = 'B';
    arra[i] += ('a' + i - 26);
  }
  for (int i = 2 * 26; i < 3 * 26; i++) {
    arra[i] = 'C';
    arra[i] += ('a' + i - (2 * 26));
  }
  for (int i = 3 * 26; i < 104; i++) {
    arra[i] = 'D';
    arra[i] += ('a' + i - (3 * 26));
  }
  for (int i = 0; i < k - 1; i++) ans.push_back(arra[i]);
  cin >> kelma;
  if (kelma == "YES")
    ans.push_back(arra[k - 1]);
  else
    ans.push_back(arra[0]);
  for (int i = 0; i < (n - k); i++) {
    cin >> kelma;
    if (kelma == "YES") {
      ans.push_back(arra[c]);
      c++;
    } else
      ans.push_back(ans[ans.size() - (k - 1)]);
  }
  for (int i = 0; i < ans.size(); i++) cout << ans[i] << ' ';
  return 0;
}
