#include <bits/stdc++.h>
using namespace std;
int names[51];
bool good[51];
void Name(int a) {
  char s[3] = "Aa";
  s[0] += a / 26;
  s[1] += a % 26;
  cout << s << " ";
}
int main() {
  int n, k;
  cin >> n >> k;
  for (int i = 0; i < n - k + 1; i++) {
    char s[6];
    cin >> s;
    if (strcmp(s, "YES"))
      good[i] = 0;
    else
      good[i] = 1;
  }
  for (int i = 0; i < k; i++) names[i] = i + 1;
  if (!good[0]) names[1] = names[0];
  for (int i = 1; i < n - k + 1; i++) {
    if (good[i])
      names[k + i - 1] = k + i;
    else
      names[k + i - 1] = names[i];
  }
  for (int i = 0; i < n; i++) Name(names[i]);
  return 0;
}
