#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  string s[52];
  for (long long int i = 0; i < 26; i += 1) {
    char x = (char)(i + 65);
    s[i] = x;
  }
  for (long long int i = 26; i < 52; i += 1) {
    char x = (char)(i - 26 + 97);
    s[i] = 'A';
    s[i] += x;
  }
  long long int n, k;
  cin >> n >> k;
  vector<string> v;
  string x;
  cin >> x;
  if (x == "YES") {
    for (long long int i = 0; i < k; i += 1) v.push_back(s[i]);
  } else {
    for (long long int i = 0; i < k - 1; i += 1) v.push_back(s[i]);
    v.push_back(s[0]);
  }
  for (long long int i = 1; i < n - k + 1; i += 1) {
    cin >> x;
    if (x == "YES") {
      for (long long int j = 0; j < 52; j += 1) {
        long long int f = 1;
        for (long long int k = i; k < v.size(); k += 1)
          if (s[j] == v[k]) f = 0;
        if (f == 1) {
          v.push_back(s[j]);
          break;
        }
      }
    } else {
      v.push_back(v[i]);
    }
  }
  for (long long int i = 0; i < v.size(); i += 1) cout << v[i] << " ";
  return 0;
}
