#!/usr/bin/env python3
# %%
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
from collections import defaultdict

# %%
N, D, T, *X = map(int, read().split())

# %%
X_class = defaultdict(list)
for x in X:
    q, r = divmod(x, D)
    X_class[r].append(q)


# %%
def solve(Q):
    Q.sort()
    INF = 10 ** 30
    right_end = -INF
    ret = 0
    for q in Q:
        if right_end >= q:
            x = q + T + T
            ret += x - right_end
            right_end = x
        else:
            right_end = q + T + T
            ret += T + T + 1
    return ret


# %%
answer = sum(solve(value) for key, value in X_class.items())
print(answer)