#include <bits/stdc++.h>
using namespace std;
string s[105];
int main() {
  int n, k;
  cin >> n >> k;
  for (int i = 1; i <= n; i++) {
    s[i] = "Aa";
    s[i][0] += i / 26;
    s[i][1] += i % 26;
  }
  for (int i = 1; i <= n - k + 1; i++) {
    string x;
    cin >> x;
    if (x == "NO") s[i + k - 1] = s[i];
  }
  for (int i = 1; i <= n; i++) cout << s[i] << " ";
  cout << endl;
  return 0;
}
