#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, len;
  cin >> n >> k;
  len = n - k + 1;
  string s;
  int A[50] = {0};
  for (int i = 0; i < len; i++) {
    cin >> s;
    if (s == "NO") {
      A[i + k - 1] = 1;
    }
  }
  for (int i = 1; i < n; i++) {
    if (A[i] == 1) {
      A[i] = A[i - k + 1];
    } else {
      A[i] = i;
    }
  }
  for (int i = 0; i < n; i++) {
    switch (A[i] % 3) {
      case 0:
        s = "A";
        break;
      case 1:
        s = "B";
        break;
      case 2:
        s = "C";
        break;
    }
    switch (A[i] % 4) {
      case 0:
        s += "a";
        break;
      case 1:
        s += "b";
        break;
      case 2:
        s += "c";
        break;
      case 3:
        s += "d";
        break;
    }
    switch (A[i] % 5) {
      case 0:
        s += "a";
        break;
      case 1:
        s += "b";
        break;
      case 2:
        s += "c";
        break;
      case 3:
        s += "d";
        break;
      case 4:
        s += "e";
        break;
    }
    cout << s << " ";
  }
  return 0;
}
