#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  cin >> n >> k;
  string s1[n - k + 1];
  string s2[52];
  int count = 65;
  for (int i = 1; i <= 51; ++i) {
    if (i <= 26) {
      s2[i] = count;
      ++count;
    } else {
      s2[i] = (char)(count - 26);
      s2[i] += 'a';
      ++count;
    }
  }
  int ans[53];
  for (int i = 1; i <= 50; ++i) ans[i] = i;
  count = k;
  for (int i = 0; i < n - k + 1; ++i) {
    cin >> s1[i];
    if (s1[i] == "NO") {
      ans[count] = ans[count - k + 1];
    }
    ++count;
  }
  for (int i = 1; i <= n; ++i) {
    cout << s2[ans[i]] << " ";
  }
  return 0;
}
