#include <bits/stdc++.h>
using namespace std;
int n, k;
string res[55];
string ss[55];
int main() {
  cin.sync_with_stdio(false);
  cin >> n >> k;
  for (int i = (int)(0); i < (int)(2); i++) {
    for (int j = (int)(0); j < (int)(26); j++) {
      ss[i * 26 + j] = 'a' + j;
      ss[i * 26 + j] = (i == 0 ? "A" : "B") + ss[i * 26 + j];
    }
  }
  for (int i = (int)(0); i < (int)(k - 1); i++) res[i] = ss[i];
  int pre = k - 1;
  for (int i = (int)(k - 1); i < (int)(n); i++) {
    string s;
    cin >> s;
    if (s == "YES") {
      res[i] = ss[++pre];
    } else {
      res[i] = res[i - k + 1];
    }
  }
  for (int i = (int)(0); i < (int)(n); i++)
    printf("%s%c", res[i].c_str(), i == n - 1 ? '\n' : ' ');
  return 0;
}
