#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, i, t, k3;
  char s1[13];
  map<int, string> s;
  k = 1;
  t = 65;
  for (k3 = 1; k3 <= 26; k3++) {
    s[k3] = t;
    t++;
  }
  s[27] = "Aa";
  s[28] = "Ab";
  s[29] = "Ac";
  s[30] = "Ad";
  s[31] = "Ae";
  s[32] = "Af";
  s[33] = "Ag";
  s[34] = "Ah";
  s[35] = "Ai";
  s[36] = "Aj";
  s[37] = "Ak";
  s[38] = "Al";
  s[39] = "Am";
  s[40] = "An";
  s[41] = "Ao";
  s[42] = "Ap";
  s[43] = "Aq";
  s[44] = "Ar";
  s[45] = "As";
  s[46] = "At";
  s[47] = "Au";
  s[48] = "Av";
  s[49] = "Aw";
  s[50] = "Ax";
  s[51] = "Ay";
  cin >> n >> k;
  for (i = 1; i <= (n - k + 1); i++) {
    cin >> s1;
    if (strcmp(s1, "NO") == 0) {
      s[i + k - 1] = s[i];
    }
  }
  for (i = 1; i <= n; i++) {
    cout << s[i] << " ";
  }
}
