#include <bits/stdc++.h>
using namespace std;
const int maxn = 405;
void solve() {
  string names[55];
  for (int i = 0; i < 55; i++) {
    string ns = "";
    char first = char('A' + (i / 26));
    char second = char('a' + (i % 26));
    ns += first;
    ns += second;
    names[i] = ns;
  }
  int n, k;
  cin >> n >> k;
  string ans[55];
  for (int i = 0; i < n - k + 1; i++) {
    string p;
    cin >> p;
    if (p == "YES") {
      set<string> ss;
      int j = i;
      int kp = 0;
      while (j < i + k) {
        if (ans[j].size() > 0) {
          ss.insert(ans[j]);
        } else {
          while (ss.count(names[kp])) kp++;
          ans[j] = names[kp++];
        }
        j += 1;
      }
    } else {
      if (ans[i].size() == 0) {
        ans[i] = ans[i + 1] = names[0];
      } else {
        int j = i;
        while (ans[j].size() > 0) j += 1;
        ans[j] = ans[i];
      }
    }
  }
  for (int i = 0; i < n; i++) {
    if (ans[i].size() > 0)
      cout << ans[i] << " ";
    else {
      cout << names[0] << " ";
    }
  }
  cout << endl;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(nullptr);
  cout.tie(nullptr);
  cout.precision(10);
  cout << fixed;
  solve();
  return 0;
}
