#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  long long n, k;
  cin >> n >> k;
  string s[n - k + 1];
  for (long long i = 0; i <= n - k; i++) cin >> s[i];
  string c[50];
  long long i1 = 65;
  for (long long i = 0; i < 26; i++) {
    c[i] = i1;
    i1++;
  }
  i1 = 65;
  for (long long i = 26; i < 50; i++) {
    c[i] = i1;
    c[i] += 'a';
    i1++;
  }
  string ans[n];
  i1 = 0;
  for (long long i = 0; i < n; i++) {
    ans[i] = c[i1];
    i1++;
  }
  for (long long i = 0; i <= n - k; i++) {
    if (s[i] == "NO") {
      ans[i + k - 1] = ans[i];
    }
  }
  for (long long i = 0; i < n; i++) cout << ans[i] << " ";
  return 0;
}
