#coding: UTF-8

import sys
import re
import itertools
from math import log
from collections import deque

### defs ###


### main ###
N = int(sys.stdin.readline())
A = list(map(int, sys.stdin.readline().split()))

sorted(A)
A = [0] + A + [0]
ans=0
for i in range(1,N+1):
	if (A[i-1]!=A[i] and A[i]!=A[i+1]):
		ans+=1
print(ans)