#include <bits/stdc++.h>
using namespace std;
vector<string> ans;
map<string, int> lo;
string s[100], V[55];
long long int n, m, k, done[100], fyes = -1;
void give() {
  string T = "abcdef";
  do {
    ans.push_back(T);
  } while (next_permutation(T.begin(), T.end()));
  for (int i = 0; i < ans.size(); i++) lo[ans[i]] = i;
}
int main() {
  give();
  cin >> n >> k;
  for (int i = 0; i < (n - k + 1); i++) {
    cin >> s[i];
    if (s[i] == "YES" && fyes == -1) fyes = i;
  }
  if (fyes != -1) {
    for (int i = fyes, j = 0; j < k; i++, j++) V[i] = ans[j];
    for (int i = fyes + 1; i < n - k + 1; i++) {
      if (s[i] == "YES") {
        V[i + k - 1] = ans[lo[V[i]] + k - 1];
      } else {
        V[i + k - 1] = V[i];
      }
    }
    for (int i = 0; i < fyes; i++) V[i] = V[fyes];
  } else {
    for (int i = 0; i < n; i++) V[i] = "fuchka";
  }
  for (int i = 0; i < n; i++) {
    V[i][0] = V[i][0] + 'A' - 'a';
    cout << V[i] << " ";
  }
}
