#include <bits/stdc++.h>
using namespace std;
vector<string> names;
int main() {
  int n, k;
  string te, t;
  cin >> n >> k;
  for (int i = 0; i < n; i++) {
    names.push_back("");
    t = i / 26 + 'A';
    names[i] += t;
    t = i % 26 + 'a';
    names[i] += t;
  }
  for (int i = 0; i < n - k + 1; i++) {
    cin >> te;
    if (te[0] == 'N') {
      names[i + k - 1] = names[i];
    }
  }
  for (int i = 0; i < n; i++) {
    cout << names[i] << ' ';
  }
  cout << endl;
}
