#include <bits/stdc++.h>
using namespace std;
int getInt() {
  int x;
  scanf("%d", &x);
  return x;
}
long long getLongLong() {
  long long x;
  scanf("%I64d", &x);
  return x;
}
double getDouble() {
  double x;
  scanf("%lf", &x);
  return x;
}
char getChar() {
  char x;
  scanf("%c", &x);
  return x;
}
template <typename t>
t abs(t a) {
  if (a >= 0) return a;
  return -a;
}
vector<string> split(const string& s, char c) {
  vector<string> v;
  stringstream second(s);
  string x;
  while (getline(second, x, c)) v.emplace_back(x);
  return move(v);
}
void err(vector<string>::iterator it) {}
template <typename T, typename... Args>
void err(vector<string>::iterator it, T a, Args... args) {
  cout << it->substr((*it)[0] == ' ', it->length()) << " = " << a << "  ";
  err(++it, args...);
}
void FastIO() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.precision(20);
}
string toStr(int x) {
  string ans;
  if (x < 26)
    ans.push_back((char)(x + 'A'));
  else {
    ans = "Az";
    x -= 26;
    ans.push_back((char)(x + 'a'));
  }
  return ans;
}
int idx = 0;
int getId() { return idx++; }
int main() {
  int n, k, a[100];
  n = getInt();
  k = getInt();
  int t = n - k + 1;
  vector<int> q;
  string s;
  for (int i = 0; i < t; i++) {
    cin >> s;
    if (s == "YES")
      q.push_back(1);
    else
      q.push_back(0);
  }
  for (int i = n - 1; i >= t; i--) a[i] = getId();
  for (int i = t - 1; i >= 0; i--) {
    if (q[i] == 1)
      a[i] = getId();
    else
      a[i] = a[i + (k - 1)];
  }
  for (int i = 0; i < n; i++) {
    cout << toStr(a[i]) << " ";
  }
  return 0;
}
