from collections import defaultdict

N, D, T = map(int, input().split())
X = list(map(int, input().split()))
dic = defaultdict(list)

for x in X:
    dic[x % D].append(x)

INF = 10 ** 20
ans = 0
for V in dic.values():
    r = - INF
    l = -INF
    for v in V:
        if r < v - D * (T + 1):
            ans += (r - l) // D
            l = v - D * (T + 1)
            r = v + D * T
        else:
            r = v + (D * T)
    ans += (r - l)//D
print(ans)