from typing import List, Tuple
N, D, T = map(int, input().split())
X = list(map(int, input().split()))
amoeba: List[Tuple[int, int]] = []
for x in X:
    d = x % D
    if x < 0:
        d += D
    amoeba.append((x, d))
amoeba.sort(key=lambda it: (it[1], it[0]))
ans = 0
for i, a in enumerate(amoeba):
    if i == 0 or amoeba[i - 1][1] != a[1]:
        ans += T
    else:
        ans += min((a[0] - amoeba[i - 1][0]) // D - 1, T * 2)
    if i == len(amoeba) - 1 or amoeba[i + 1][1] != a[1]:
        ans += T
    ans += 1
print(ans)