#include <bits/stdc++.h>
using namespace std;
const int N = 2e6 + 7;
const int M = 4e6 + 7;
const int lim = 1e6;
const int mod = 1e4;
const double inf = 0x3f3f3f3f;
const double PI = acos(-1);
int a[N], b[N];
string fun(int x) {
  string st = "";
  st += (x / 26 + 'A');
  st += (x % 26 + 'a');
  return st;
}
int main() {
  int n, k, cnt = 0;
  scanf("%d%d", &n, &k);
  for (int i = 1; i < k; i++) a[i] = ++cnt;
  for (int i = k; i <= n; i++) {
    string ss;
    cin >> ss;
    if (ss == "NO")
      a[i] = a[i - k + 1];
    else
      a[i] = ++cnt;
  }
  for (int i = 1; i <= n; i++) cout << fun(a[i]) << " ";
  return 0;
}
