n=int(input())
a=[int(i) for i in input().split()]
a.sort()
ans=0
for i in range(len(a)):
    if i==0:
        if a[i]!=a[i+1]:
            ans+=1
    elif i==len(a)-1:
        if a[i]!=a[i-1]:
            ans+=1
    else:
        if a[i]!=a[i-1] and a[i]!=a[i+1]:
            ans+=1
print(ans)