#include <bits/stdc++.h>
using namespace std;
const int MX_SZ = 52;
int main() {
  int n, k;
  cin >> n >> k;
  int a[MX_SZ];
  for (int i = 0; i < n - k + 1; ++i) {
    string s;
    cin >> s;
    if (s == "YES") {
      a[i] = 1;
    } else {
      a[i] = 0;
    }
  }
  string ans[MX_SZ];
  for (int i = 0; i < k - 1; ++i) {
    ans[i] = char('A' + i % 26);
    if (i >= 26) {
      char c = 'a' + (i - 26);
      ans[i] += c;
    }
  }
  int nw = k - 1;
  int ptr = k - 1;
  for (int i = 0; i < n - k + 1; ++i) {
    if (a[i] == 1) {
      ans[ptr] = char('A' + nw % 26);
      if (nw >= 26) {
        char c = 'a' + (nw - 26);
        ans[ptr] += c;
      }
      ++nw;
    } else {
      ans[ptr] = ans[ptr - k + 1];
    }
    ++ptr;
  }
  for (int i = 0; i < n; ++i) {
    cout << ans[i] << " ";
  }
}
