#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  scanf("%d %d", &n, &k);
  vector<string> ans;
  int in[n - k + 1];
  for (int i = 0; i < n - k + 1; i++) {
    char tmp[4];
    scanf("%s", &tmp);
    in[i] = 1 ? tmp[0] == 'Y' : 0;
  }
  char curr[3] = "Aa";
  int i;
  for (i = 0; i < k - 1; i++) {
    if (curr[1] != 'z')
      curr[1]++;
    else {
      curr[0]++;
      curr[1] = 'a';
    }
    ans.push_back(curr);
  }
  for (i = i; i < n; i++) {
    if (!in[i - k + 1])
      ans.push_back(ans[i - k + 1]);
    else {
      if (curr[1] != 'z')
        curr[1]++;
      else {
        curr[0]++;
        curr[1] = 'a';
      }
      ans.push_back(curr);
    }
  }
  for (int i = 0; i < n; i++) cout << ans[i] << " ";
}
