#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
const int inf = 0x3f3f3f3f;
const double eps = 1e-7;
int n, k;
string ans[60];
int a[60];
map<int, int> mm;
int main() {
  ios::sync_with_stdio(false);
  cin >> n >> k;
  for (int i = 1; i <= n; i++) {
    if (i <= 26)
      ans[i] += 'A' + i - 1;
    else
      ans[i] += 'A', ans[i] += 'a' + i - 27;
  }
  for (int i = k; i <= n; i++) {
    string s;
    cin >> s;
    if (s == "NO") ans[i] = ans[i - k + 1];
  }
  for (int i = 1; i <= n; i++) cout << ans[i] << ' ';
  cout << endl;
  return 0;
}
