#include <bits/stdc++.h>
using namespace std;
char j;
long long n, i, uk, k;
vector<string> v;
string a[111], s[111];
int main() {
  cin >> n >> k;
  for (i = 1; i <= n - k + 1; ++i) {
    cin >> a[i];
  }
  for (j = 'a'; j <= 'z'; ++j) {
    string ss = "A";
    ss += j;
    v.push_back(ss);
  }
  for (j = 'a'; j <= 'z'; ++j) {
    string ss = "A";
    ss += j;
    ss += j;
    v.push_back(ss);
  }
  long long sh = 0, x, l, t = 0;
  for (i = 1; i <= n - k + 1; ++i) {
    if (a[i] == "NO") {
      v[i + k - 1] = v[i];
    }
  }
  for (i = 1; i <= n; ++i) {
    cout << v[i] << ' ';
  }
  return false;
}
