# -*- coding: utf-8 -*-

n = int(input())
a = list(map(int,input().split()))

a.sort()

a = ["x"] + a + ["x"]
new = []

for i in range(1,n+1):
    if a[i] != a[i-1] and a[i] != a[i+1]:
        new.append(a[i])

print(len(new))