#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, k;
  cin >> n >> k;
  string *s = new string[100];
  for (int i = 0; i < 100; ++i) {
    s[i] = "aa";
    s[i][0] = 'A' + i / 26;
    s[i][1] = 'a' + i % 26;
  }
  string *ans = new string[n];
  for (int i = 0; i < k - 1; ++i) ans[i] = s[i];
  int pos = k + 1;
  for (int i = k - 1; i < n; ++i) {
    string ss;
    cin >> ss;
    if (ss == "YES")
      ans[i] = s[++pos];
    else
      ans[i] = ans[i - k + 1];
  }
  for (int i = 0; i < n; ++i) cout << ans[i] << " ";
  cout << endl;
  return 0;
}
