#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007;
const int inf = 1e9;
long long powmod(long long a, long long b) {
  long long res = 1;
  a %= mod;
  assert(b >= 0);
  for (; b; b >>= 1) {
    if (b & 1) res = res * a % mod;
    a = a * a % mod;
  }
  return res;
}
string createStr(int a) {
  string s;
  while (a > 0) {
    s += a % 26 + 'a';
    a /= 26;
  }
  s[0] = s[0] - 'a' + 'A';
  return s;
}
int mas[51];
int main() {
  ios_base::sync_with_stdio(0);
  int n, k;
  string s;
  cin >> n >> k;
  int curr = 1;
  for (int i = 0; i < k - 1; i++) {
    mas[i] = curr++;
  }
  for (int i = k - 1; i < n; i++) {
    cin >> s;
    if (s == "NO") {
      mas[i] = mas[i - k + 1];
    } else {
      mas[i] = curr++;
    }
  }
  for (int i = 0; i < n; i++) {
    cout << createStr(mas[i]) << ' ';
  }
  return 0;
}
