#include <bits/stdc++.h>
using namespace std;
long long i, j, k, l, m, n, q, p, r, c, d, f, t, e, mn, pas, ans,
    fx[int(2e5 + 10)];
string a[3000];
string as[300];
map<pair<long long, long long>, long long> mp;
long long C = 0;
string s = "Aa";
void nw() {
  if (s[1] == 'z') {
    s[0]++;
    s[1] = 'a';
  } else
    s[1]++;
  C++;
}
int main() {
  cin >> n >> m;
  for (int i = 0; i <= n - m; i++) {
    cin >> a[i];
  }
  for (int i = 0; i < n; i++) as[i] = s, nw();
  for (int j = n - m; j >= 0; j--) {
    if (a[j] == "NO") {
      as[j] = as[j + m - 1];
    }
  }
  for (int i = 0; i < n; i++) {
    cout << as[i] << " ";
  }
  return 0;
}
