#include <bits/stdc++.h>
using std::cin;
using std::cout;
using std::endl;
const int MaxN = 60;
bool yes[MaxN];
int seq[MaxN];
int sum(int *s, int pos, int count) {
  int t = 0;
  for (int i = 0; i < count; ++i) {
    t += s[pos + i];
  }
  return t;
}
std::string get_string(int i) {
  std::string s;
  if (i <= 25) {
    s.push_back('A' + i);
  } else {
    s.push_back('A');
    s.push_back('a' + (i % 25));
  }
  return s;
}
int main(int argc, char **argv) {
  int n, k;
  cin >> n >> k;
  std::string y;
  for (int i = 0; i < n - k + 1; ++i) {
    cin >> y;
    if (y == "YES") {
      yes[i] = true;
    } else {
      yes[i] = false;
    }
  }
  for (int i = 0; i < k; ++i) {
    seq[i] = i;
  }
  if (!yes[0]) {
    seq[k - 1] = 0;
  }
  for (int i = k; i < n; ++i) {
    if (yes[i - k]) {
      if (yes[i - k + 1]) {
        seq[i] = seq[i - k];
      } else {
        seq[i] = seq[i - k + 1];
      }
    } else {
      if (yes[i - k + 1]) {
        seq[i] = (k - 1) * k / 2 - sum(seq, i - k + 1, k - 1);
      } else {
        seq[i] = seq[i - k + 1];
      }
    }
  }
  for (int i = 0; i < n; ++i) {
    cout << get_string(seq[i]) << " ";
  }
  cout << endl;
  return 0;
}
