#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  long long j, sum, kmax, g, q, m, v, t, n, maxd, minkol, x, y, z, f, k, l, r,
      i, kol;
  cin >> n;
  cin >> k;
  string s, s1;
  vector<long long> a(n);
  for (i = 0; i < n; i++) {
    a[i] = i;
  }
  for (i = 0; i <= n - k; i++) {
    cin >> s;
    if (s == "NO") {
      a[i + k - 1] = a[i];
    }
  }
  for (i = 0; i < n; i++) {
    x = a[i];
    s1 = "";
    z = 0;
    if (a[i] >= 26) {
      s1 = s1 + 'A';
      a[i] = a[i] - 26;
      z = 1;
    }
    if (z == 1) {
      char c = 'a' + a[i];
      s1 = s1 + c;
    } else {
      char c = 'A' + a[i];
      s1 = s1 + c;
    }
    cout << s1 << " ";
  }
  return 0;
}
