import strutils,sequtils,algorithm,math

type
    ameba = tuple[x : int , md : int]
var
    N,D,T : int
    Ame = newSeq[ameba](0)
    X : seq[int]
    d : int
    ans : int64
(N, D, T) = stdin.readline.split.map(parseInt)
X = stdin.readline.split.map(parseInt)
for x in X:
    d = x mod D
    if x < 0:
        d += D
    Ame.add((x,d))

Ame = Ame.sortedByIt((it.md,it.x))
for i,a in Ame:
    if i == 0 or Ame[i - 1].md != a.md:
        ans += T
    else:
        ans += min((a.x - Ame[i - 1].x) div D - 1,T * 2)
    if i == Ame.high or Ame[i + 1].md != a.md:
        ans += T
    ans += 1
echo ans