#include <bits/stdc++.h>
using namespace std;
int n, d;
bool state[50];
string s[50], c;
int main() {
  for (int i = 0; i < 50; i++) {
    s[i] += char('A' + (i % 26));
    if (i >= 26) s[i] += 'a';
  }
  scanf("%d%d", &n, &d);
  for (int i = 0, lim = n - d + 1; i < lim; i++) {
    cin >> c;
    state[i] = (c[0] == 'Y');
  }
  for (int i = n - 1, j = n - d; j >= 0; i--, j--) {
    if (!state[j])
      for (int k = n - 1; k >= i; k--)
        if (s[k] == s[i]) s[k] = s[i - d + 1];
  }
  for (int i = 0; i < n; i++) cout << s[i] << ' ';
}
