N = int(raw_input())
A = map(int, raw_input().split())
A.sort()
cnt = 0
flag = False
tmp = -1
for i in range(0, N):
	if flag:
		if A[i] != tmp:
			cnt += 1
		else:
			flag = False
	else:
		if A[i] != tmp:
			flag = True
	tmp = A[i]
if flag:
	cnt += 1
print cnt