#include <bits/stdc++.h>
using namespace std;
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V>
void __print(const pair<T, V> &x) {
  cerr << '{';
  __print(x.first);
  cerr << ',';
  __print(x.second);
  cerr << '}';
}
template <typename T>
void __print(const T &x) {
  int first = 0;
  cerr << '{';
  for (auto &i : x) cerr << (first++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v)) cerr << ", ";
  _print(v...);
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n, k;
  cin >> n >> k;
  vector<string> s;
  for (int i = 0; i < n; i++) {
    string tt;
    cin >> tt;
    s.push_back(tt);
  }
  vector<string> names;
  vector<string> allNames;
  string al = "abcdefghijklmnopqrstuvwxyz";
  int point = 0;
  for (int i = 0; i < 26; i++) {
    string ss(1, 'A' + i);
    allNames.push_back(ss);
    point++;
  }
  point = 0;
  string cu = "A";
  for (int i = 0; i < 26; i++) {
    allNames.push_back(cu + al[point]);
    point++;
  }
  for (int i = 0; i < n; i++) {
    names.push_back(allNames[i]);
  }
  for (int i = 0; i + k <= n; i++) {
    string res = s[i];
    if (res == "NO") {
      names[i + k - 1] = names[i];
    }
  }
  for (string a : names) {
    cout << a << " ";
  }
  cout << endl;
  return 0;
}
