#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  cin >> n >> k;
  string b;
  string a[n];
  for (int i = 0; i < n; i++) {
    a[i] = 'A' + i / 26;
    a[i] += 'a' + i % 26;
  }
  for (int i = 0; i < n - k + 1; i++) {
    cin >> b;
    if (b[0] == 'N') {
      a[i + k - 1] = a[i];
    }
  }
  for (int i = 0; i < n; i++) {
    cout << a[i] << " ";
  }
  return 0;
}
