#include <bits/stdc++.h>
using namespace std;
int n, k;
string a[55], ans[55], temp[55];
int ans1[55] = {0};
vector<int> v;
int main() {
  cin >> n >> k;
  for (int i = 0; i < 54; i++) ans[i] = temp[i] = "";
  for (int i = 0; i < n - k + 1; i++) cin >> a[i];
  int i = 0, l = 1;
  while (i <= n - k) {
    if (a[i] == "YES") {
      for (int j = i; j < i + k; j++) {
        if (ans1[j] == 0) {
          ans1[j] = l;
          l++;
        }
      }
      i++;
      continue;
    } else {
      int j = i;
      while (ans1[j] != 0) j++;
      if (ans1[i] == 0) {
        ans1[i] = ans1[i + 1] = l;
        l++;
      } else {
        ans1[j] = ans1[i];
      }
      i++;
      if (i > n - k) {
        int j = i;
        while (ans1[j] != 0) j++;
        while (j < n) {
          ans1[j] = ans1[i];
          j++;
        }
      }
      continue;
    }
  }
  for (int i = 0; i < 9; i++) v.push_back(i);
  for (int i = 1; i < l; i++) {
    next_permutation(v.begin(), v.end());
    string a2 = "";
    for (int j = 0; j < 9; j++) {
      if (j == 0)
        a2 = a2 + (char)('Z' - v[j]);
      else
        a2 = a2 + (char)('z' - v[j]);
    }
    temp[i] = a2;
  }
  for (int i = 0; i < n; i++) {
    ans[i] = temp[ans1[i]];
  }
  for (int i = 0; i < n; i++) cout << ans[i] << " ";
  cout << "\n";
  return 0;
}
