#include <bits/stdc++.h>
using namespace std;
int n, k;
vector<string> name;
string getName(int i) {
  char c = i + 65;
  if (i >= 26) {
    i -= 26;
    return string("") + (char)(i + 65) + (char)(i + 97);
  } else
    return string("") + c;
}
int main() {
  cin >> n >> k;
  for (int i = 0; i < k - 1; ++i) {
    name.push_back(getName(i));
  }
  string tmp;
  for (int i = k - 1; i < n; ++i) {
    cin >> tmp;
    if (tmp == "YES")
      name.push_back(getName(i));
    else
      name.push_back(name[i - k + 1]);
  }
  for (int i = 0; i < n; ++i) {
    cout << name[i] << "  "[i + 1 == n];
  }
  return 0;
}
