#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
const double eps = 1e-8;
char a[55];
char b[55];
int main() {
  ios_base::sync_with_stdio(0);
  int n, k;
  string str;
  while (cin >> n >> k) {
    char c1 = 'A';
    char c2 = 'a';
    for (int i = 1; i <= n; ++i) {
      a[i] = c1;
      b[i] = c2;
      ++c2;
      if (c2 > 'z') {
        c2 = 'a';
        ++c1;
      }
    }
    for (int i = 1; i <= n - k + 1; ++i) {
      cin >> str;
      if (str[0] == 'N') {
        a[i + k - 1] = a[i];
        b[i + k - 1] = b[i];
      }
    }
    for (int i = 1; i <= n; ++i) cout << a[i] << b[i] << " ";
    cout << "\n";
  }
  return 0;
}
