import sys
input=lambda: sys.stdin.readline().rstrip()
n,d,t=map(int,input().split())
X=[int(i) for i in input().split()]
import collections
D=collections.defaultdict(list)
for x in X:
  D[x%d].append(x)
ans=0
for x in D.keys():
  A=D[x]
  A.sort()
  ans+=((A[-1]+d*t)-(A[0]-d*t))//d+1
print(ans)