#include <bits/stdc++.h>
std::string get_name(int id) {
  char s[3];
  s[0] = (id / 26) + 'A';
  s[1] = (id % 26) + 'a';
  s[2] = 0;
  return std::string(s);
}
int main() {
  int n, k, uni[1000], id[1000];
  scanf("%d%d", &n, &k);
  for (int i = 0; i < n - k + 1; i++) {
    std::string msg;
    std::cin >> msg;
    uni[i] = !!(msg == "YES");
  }
  for (int i = 0; i < n; i++) id[i] = i + 1;
  for (int i = 0; i < n - k + 1; i++) {
    if (!uni[i]) id[i + k - 1] = id[i];
  }
  for (int i = 0; i < n; i++) std::cout << get_name(id[i]) << ' ';
  return 0;
}
