import sys
read=sys.stdin.buffer.read
readline=sys.stdin.buffer.readline

from sortedcontainers import SortedList
from collections import defaultdict
N,D,T,*A=map(int,read().split())
mp=defaultdict(SortedList)
for x in A:
  if not mp[x%D]: mp[x%D]=SortedList()
  mp[x%D].add(x)

ans=0
for ls in mp.values():
  pre=-2e18
  for x in ls:
    l,r=x-D*T,x+D*T
    ans+=(T<<1)+1
    if pre>=l: ans-=(pre-l+D)//D
    pre=r

print(ans)