from collections import defaultdict
N, D, T = map(int, input().split())
X = list(map(int, input().split()))

d = defaultdict(list)
for x in X:
    d[x % D].append(x)

ans = 0
for pos in d.values():
    pos.sort()
    L = pos[0] - D * T
    R = pos[0] + D * T
    for p in pos[1:]:
        l = p - D * T
        r = p + D * T
        if l <= R:
            R = r
        else:
            ans += (R - L) // D + 1
            L = l
            R = r
    ans += (R - L) // D + 1

print(ans)