#include <bits/stdc++.h>
using namespace std;
string a[55];
string b[65];
int main() {
  int n, k, t = 0, f;
  scanf("%d %d", &n, &k);
  getchar();
  for (int i = 0; i < 8; ++i) {
    for (int j = 0; j < 8; ++j) {
      char x = 'A' + i, y = 'a' + j;
      b[t].insert(b[t].end(), x), b[t].insert(b[t].end(), y);
      ++t;
    }
  }
  char p[10];
  t = 0;
  for (int i = 0; i < n - k + 1; ++i) {
    scanf("%s", p);
    getchar();
    if (p[0] == 'Y') {
      f = i;
      while (a[f].length()) ++f;
      for (; f < i + k; ++f) a[f] = b[t++];
    } else if (p[0] == 'N') {
      if (i == 0) a[i] = b[t++];
      f = i;
      while (a[f].length()) ++f;
      a[f] = a[i];
      if (i == n - k)
        for (int j = f + 1; j < i + k; ++j) a[j] = a[j - 1];
    }
  }
  for (int i = 0; i < n; ++i) {
    cout << a[i];
    if (i != n - 1) cout << " ";
  }
  cout << endl;
  return 0;
}
