import sys

input = sys.stdin.readline


def main():
    N, D, T = map(int, input().split())

    mod_dict = {}

    for x in map(int, input().split()):
        if x % D not in mod_dict:
            mod_dict[x % D] = []
        mod_dict[x % D].append(x//D)

    def calc(x):
        events = []
        for i in x:
            events.append((i-T, 1))
            events.append((i+T+1, -1))

        events.sort()
        cur = 0
        ans = 0
        for i in range(len(events)-1):
            tm, val = events[i]
            cur += val
            if cur > 0:
                ans += events[i+1][0] - tm
        return ans

    print(sum(map(calc, mod_dict.values())))


if __name__ == '__main__':
    main()