#include <bits/stdc++.h>
using namespace std;
vector<string> v;
int main() {
  long long i, j, k, l, m, n;
  string s;
  s = "abcdefghij";
  i = 1;
  do {
    string st;
    st = s;
    st[0] = 'A';
    v.push_back(st);
    i++;
    if (i == 1000) break;
  } while (std::next_permutation(s.begin(), s.end()));
  cin >> n >> m;
  vector<string> ans;
  for (i = 0; i < n; i++) {
    ans.push_back(v[i]);
  }
  for (i = 0; i < n - m + 1; i++) {
    string inp;
    cin >> inp;
    if (inp == "NO") {
      ans[m + i - 1] = ans[i];
    }
  }
  for (i = 0; i < n; i++) {
    cout << ans[i] << " ";
  }
  cout << endl;
  return 0;
}
