#include <bits/stdc++.h>
using namespace std;
string s(int n) {
  char l = n / 9 + 'a';
  char L = n / 9 + 'A';
  n %= 9;
  string result = string("") + L;
  result.resize(n + 1, l);
  return result;
}
int main() {
  int n, k;
  cin >> n >> k;
  int used = 0;
  vector<int> data(n);
  for (int i = 0; i < k - 1; i++) {
    data[i] = used;
    used++;
    cout << s(data[i]) << " ";
  }
  for (int i = k - 1; i < n; i++) {
    string v;
    cin >> v;
    if (v == "YES") {
      data[i] = used;
      used++;
    } else {
      data[i] = data[i - k + 1];
    }
    cout << s(data[i]) << " ";
  }
}
