#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("Ofast", "unroll-loops")
const int MAXN = 1e5 * 2;
string format(int n) {
  string ans = "A";
  if (n <= 26) {
    ans += 'a' + n - 1;
    return ans;
  }
  ans += 'a';
  n -= 26;
  ans += 'a' + n - 1;
  return ans;
}
int main() {
  ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
  42;
  int n, k, a, b, t = 0;
  cin >> n >> k;
  vector<int> p;
  for (int i = 1; i <= n - k + 1; i++) {
    string s;
    cin >> s;
    if (s[0] == 'Y') {
      p.push_back(1);
    } else
      p.push_back(0);
  }
  vector<int> ans(n + 1);
  for (int i = 1; i < k; i++) {
    t++, ans[i] = t;
  }
  int i = k;
  for (auto it : p) {
    if (it) {
      t++, ans[i] = t;
    } else {
      42;
      ans[i] = ans[(i - k) + 1];
    }
    i++;
  }
  for (int i = 1; i <= n; i++) cout << format(ans[i]) << " ";
}
