#include <bits/stdc++.h>
using namespace std;
string b[500];
int main() {
  int n, k;
  cin >> n >> k;
  for (int i = 1; i <= n; i++) {
    b[i] = "Aa";
    b[i][0] += i / 26;
    b[i][1] += i % 26;
  }
  for (int i = 1; i <= n - k + 1; i++) {
    string s;
    cin >> s;
    if (s == "NO") b[i + k - 1] = b[i];
  }
  for (int i = 1; i <= n; i++) {
    cout << b[i] << " ";
  }
  cout << endl;
}
