#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 100;
const int inf = 1e9 + 7;
const int mod = 1e9 + 7;
const double pi = acos(-1);
int n, k, used[1000];
string com[1010];
string ans[1010];
string make(int p) {
  string s = "";
  if (p >= 26)
    s += "A", p -= 26, s += char(p + 'a');
  else
    s += char(p + 'A');
  return s;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> n >> k;
  for (int i = 1; i <= n - k + 1; i++) {
    cin >> com[i];
  }
  for (int i = 1; i < k; i++) {
    used[i] = 1;
    ans[i] = make(i);
  }
  for (int i = 1; i <= n - k + 1; i++) {
    if (com[i] == "YES") {
      for (int j = 1; j <= 52; j++) {
        if (used[j] == 0) {
          ans[i + k - 1] = make(j), used[j] = 1;
          break;
        }
      }
    } else {
      ans[i + k - 1] = ans[i];
    }
  }
  for (int i = 1; i <= n; i++) cout << ans[i] << ' ';
  return 0;
}
