import sys
input=lambda:sys.stdin.readline().rstrip()
N,D,T=map(int,input().split())
X=list(map(int,input().split()))
ans=N
pos=[[] for i in range(D)]
for i in X:
	pos[i%D].append(i//D)
for i in range(D):
	pos[i]=sorted(pos[i])
	if len(pos[i])==0:
		continue
	ans+=2*T
	for j in range(len(pos[i])-1):
		ans+=min(2*T,pos[i][j+1]-pos[i][j]-1)
print(ans)