#include <bits/stdc++.h>
using namespace std;
const int N = 60;
char A[N];
string random(int len) {
  string res(len, ' ');
  for (int i = 0; i < len; ++i)
    if (!i)
      res[i] = char('A' + rand() % 26);
    else
      res[i] = char('a' + rand() % 26);
  return res;
}
string a[N];
void gen(int n) {
  set<string> cur;
  for (int i = 0; i < n; ++i) {
    string to = random(rand() % 10 + 1);
    while (cur.count(to)) to = random(rand() % 10 + 1);
    cur.insert(to);
    a[i] = to;
  }
}
int main() {
  int n, k;
  cin >> n >> k;
  for (int i = 0; i < n - k + 1; ++i) {
    string c;
    cin >> c;
    if (c == "YES") A[i] = 1;
  }
  gen(n);
  for (int i = 0; i < n - k + 1; ++i)
    if (!A[i]) a[i + k - 1] = a[i];
  for (int i = 0; i < n; ++i) cout << a[i] << " ";
}
