n, d, t = map(int, input().split())
ameba = list(map(int, input().split()))
ameba.sort()

check = [0] * n
ans = 0

for i in range(n):
    if check[i]:
        continue
    a = []
    for j in range(i, n):
        if ameba[j] % d == ameba[i] % d:
            a.append(ameba[j])
            check[j] = 1

    low = a[0] - t * d
    high = a[0] + t * d

    for j in range(1, len(a)):
        nlow = a[j] - t * d
        nhigh = a[j] + t * d
        if nlow > high:
            ans += (high - low) // d + 1
            low = nlow
            high = nhigh
        else:
            high = nhigh
    
    ans += (high - low) // d + 1

print(ans)