import collections
N,D,T = map(int,input().split())
lsx = list(map(int,input().split()))
#x-T*D,x+T*DにD置きに存在modDと範囲が分かれば答えが求まる
lsmod = [i%D for i in lsx]
dic = collections.defaultdict(lambda : [])
for i in range(N):
    dic[lsmod[i]].append(lsx[i])
ans = 0
for key in dic.keys():
    ls = dic[key]
    if len(ls) == 1:
        ans += 2*T+1
        continue
    ls.sort()
    l1 = ls[0]-T*D
    r1 = ls[0]+T*D
    lslr = [[l1,r1]]
    for i in range(1,len(ls)):
        l2 = ls[i]-T*D
        r2 = ls[i]+T*D
        if l2 <= lslr[-1][1]:
            lslr[-1][1] = r2
        else:
            lslr.append([l2,r2])
    for lr in lslr:
        ans += (lr[1]-lr[0])//D+1
print(ans)