n,d,t = map(int,input().split()) X = list(map(int,input().split())) ans = 0 dic = {} for x in X: if x%d not in dic: dic[x%d] = [] dic[x%d].append(x) for lis in dic.values(): l = 0 r = 0 for x in lis: if l == r == 0: l = x-d*t r = x+d*t continue if r >= x-d*t: r = x+d*t else: ans += (r-l)//d+1 l = x-d*t r = x+d*t ans += (r-l)//d+1 print(ans)