#include <bits/stdc++.h>
using namespace std;
string names[676];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n, k;
  cin >> n >> k;
  int unique[n + 1];
  memset(unique, 1, sizeof(unique));
  for (int i = 0; i < 676; i++) {
    char x = i / 26 + 'A', y = i % 26 + 'a';
    names[i] += x, names[i] += y;
  }
  int arr[n + 1];
  memset(arr, -1, sizeof(arr));
  for (int i = 1; i <= n - k + 1; i++) {
    string s;
    cin >> s;
    if (s == "YES") {
      unique[i] = 1;
    } else {
      unique[i] = 0;
    }
  }
  for (int i = 1; i <= n; i++) {
    arr[i] = i;
  }
  for (int i = 1; i <= n - k + 1; i++) {
    if (!unique[i]) {
      arr[i + k - 1] = arr[i];
    }
  }
  for (int i = 1; i <= n; i++) {
    cout << names[arr[i]] << " ";
  }
  cout << endl;
  return 0;
}
