n, d, t = map(int, input().split())
pos = {}
X = list(map(int, input().split()))
for x in X:
    p = x % d
    x //= d
    mi = x - t
    ma = x + t
    if p not in pos:
        pos[p] = {}
    pos[p][mi] = pos[p].get(mi, 0) + 1
    pos[p][ma + 1] = pos[p].get(ma + 1 , 0) - 1
ans = 0
for dic in pos.values():
    bef = -1
    tot = 0
    for k in sorted(dic.keys()):
        v = dic[k]
        if tot > 0:
            ans += k - bef
        bef = k
        tot += v
print(ans)