from collections import defaultdict


def solve():
    N, D, T = map(int, input().split())
    X = list(map(int, input().split()))

    def count(ys):
        if len(ys) == 0:
            return 0
        mi = ys[0]
        ma = ys[-1]
        return 2 * T + 1 + ma - mi

    groups = defaultdict(list)

    for x in X:
        groups[x % D].append(x // D)

    ans = 0
    for m in groups:
        xs = groups[m]
        xs.sort()

        p = -float('inf')
        ys = []

        for x in xs:
            if abs(p - x) <= T * 2:
                ys.append(x)
            else:
                ans += count(ys)
                ys = [x]
            p = x
        ans += count(ys)

    print(ans)

if __name__ == '__main__':
    solve()