#include <bits/stdc++.h>
using namespace std;
string v[51];
string cuvant(int x) {
  string cuv;
  if (x < 26) {
    cuv = "A";
  } else {
    cuv = "B";
  }
  cuv += (char)(x % 26 + 'a');
  return cuv;
}
int main() {
  int n, k;
  string x;
  cin >> n >> k;
  for (int i = 1; i <= n; i++) {
    v[i] = cuvant(i);
  }
  for (int i = k; i <= n; i++) {
    cin >> x;
    if (i >= k && x == "NO") {
      v[i] = v[i - k + 1];
    }
  }
  for (int i = 1; i <= n; i++) {
    cout << v[i] << " ";
  }
  return 0;
}
