#include <bits/stdc++.h>
int main() {
  size_t n, k;
  scanf("%zu %zu", &n, &k);
  std::vector<char> yn(n - k + 1);
  for (auto& x : yn) scanf(" %c%*[^ ]", &x);
  std::vector<size_t> res(k - 1);
  std::iota(res.begin(), res.end(), 0);
  for (size_t i = 0; i <= n - k; ++i)
    res.push_back((yn[i] == 'Y') ? i + k - 1 : res[i]);
  std::vector<std::string> name(n);
  for (size_t i = 0; i < n; ++i) {
    name[i] += 'A' + (i / 26);
    name[i] += 'a' + (i % 26);
  }
  for (size_t i = 0; i < n; ++i)
    printf("%s%c", name[res[i]].c_str(), i + 1 < n ? ' ' : '\n');
}
