#include <bits/stdc++.h>
using namespace std;
string rslt[55];
int main() {
  int n, k, m = 0;
  cin >> n >> k;
  int s = n - k + 1;
  for (char i = 'a'; i <= 'z'; i++) {
    bool f = false;
    for (char j = 'a'; j <= 'z'; j++) {
      rslt[m] = "A";
      rslt[m] += i;
      rslt[m] += j;
      if (++m >= k) {
        f = true;
        break;
      }
    }
    if (f) break;
  }
  m = k - 1;
  string ss, sm = "Masud";
  for (int i = 0; i < s; i++) {
    cin >> ss;
    if (ss == "YES") {
      rslt[m] = sm;
      sm = rslt[m - k + 1];
    } else {
      rslt[m] = rslt[m - k + 1];
    }
    m++;
  }
  for (int i = 0; i < n; i++) cout << rslt[i] << ' ';
}
