#include<stdio.h>
int main(void){
  char *s="python3 -c\""
"n,c,k,*t=map(int,open(0).read().split())\n"
"t.sort(reverse=1)\n"
"a=0\n"
"while t:\n"
"  h=t.pop()\n"
"  i=h\n"
"  j=1\n"
"  while t and j<c and i-h<k:\n"
"    i=t.pop()\n"
"    j+=1\n"
"  if i-h>k:\n"
"    t.append(i)\n"
"  a+=1\n"
"print(a)\n"
"\"";
  system(s);
  return 0;
}            