import sys
read=sys.stdin.buffer.read
readline=sys.stdin.buffer.readline
readlines=sys.stdin.buffer.readlines

n, d, t=map(int, readline().split())
x=list(map(int, readline().split()))
mp={}
for a in x:
    r=a%d
    if r not in mp:
        mp[r]=[]
    mp[r].append(a//d)
ans=0
for v in mp.values():
    v.sort()
    v.append(10**10)
    l=v[0]
    xp=v[0]
    for x in v:
        if x-xp>2*t:
            ans+=xp-l+1+2*t
            l=x
        xp=x
print(ans)