#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, i, name[100], cnt;
  string str;
  char ch;
  cin >> n >> k;
  cnt = 0;
  for (i = 1; i <= k - 1; i++) {
    name[i] = ++cnt;
  }
  for (i = k; i <= n; i++) {
    cin >> str;
    if (str[0] == 'N') {
      name[i] = name[i - k + 1];
    } else {
      name[i] = ++cnt;
    }
  }
  for (i = 1; i <= n; i++) {
    if (name[i] <= 26) {
      ch = ('A' - 1) + name[i];
      str = ch;
    } else {
      ch = ('a') + name[i] - 26;
      str = 'A';
      str = str + ch;
    }
    cout << str << " ";
  }
}
