from collections import defaultdict
import sys
readline=sys.stdin.readline

N,D,T=map(int,readline().split())
dct=defaultdict(list)
for x in map(int,readline().split()):
    dct[x%D].append(x)
ans=0
for lst in dct.values():
    lst=sorted([x//D for x in lst])
    l=len(lst)
    ans+=l
    ans+=2*T
    for i in range(l-1):
        ans+=min(lst[i+1]-lst[i]-1,2*T)
print(ans)