#include <bits/stdc++.h>
char getch() {
  char ch;
  ch = fgetc(stdin);
  while (ch == ' ' || ch == '\n') ch = fgetc(stdin);
  return ch;
}
void scrie(int x) {
  if (x < 26)
    fputc('A' + x, stdout);
  else {
    fputc('A' + x / 26, stdout);
    fputc('a' + x % 26, stdout);
  }
  printf(" ");
}
int v[50];
int main() {
  int n, k, x;
  scanf("%d%d", &n, &k);
  for (int i = 0; i < n; ++i) v[i] = i;
  for (int i = 0; i < n - k + 1; ++i) {
    char ch = getch();
    if (ch == 'N')
      getch();
    else {
      getch();
      getch();
    }
    if (ch == 'N') v[i + k - 1] = v[i];
  }
  for (int i = 0; i < n; ++i) scrie(v[i]);
  return 0;
}
