#include <bits/stdc++.h>
using namespace std;
string convert(int n) {
  string s;
  if (n < 26) {
    s += 'A';
  } else {
    s += 'B';
  }
  n = n % 26;
  char adds = 'a' + n;
  s += adds;
  return s;
}
int main() {
  int n, k;
  cin >> n >> k;
  vector<bool> checks(n - k + 1, false);
  for (int i = 0; i < n - k + 1; i++) {
    string yes;
    cin >> yes;
    if (yes == "YES") {
      checks[i] = true;
    }
  }
  vector<int> nums(n, 0);
  for (int i = 0; i < k - 1; i++) {
    nums[i] = i;
  }
  for (int i = k - 1; i < n; i++) {
    if (checks[i - k + 1]) {
      nums[i] = i;
    } else {
      nums[i] = nums[i - k + 1];
    }
  }
  for (int i = 0; i < n; i++) {
    cout << convert(nums[i]) << " ";
  }
}
