import sys
#sys.setrecursionlimit(n)
import heapq
import re
import bisect
import random
import math
import itertools
from collections import defaultdict, deque, OrderedDict
from copy import deepcopy

N, D, T = map(int, input().split())

L = deque(list(map(int, input().split())))
V = defaultdict(list)
for l in L:
  x = (l + 10 ** 9) % D
  V[x].append((l + 10 ** 9) // D)
count = 0
for v in V:
  a = V[v]
  a.sort()
  m = -(10 ** 9)
  for i in a:
    right = i + T
    left = i - T
    if m >= left:
      left = m + 1
    count += right - left + 1
    m = right
print(count)