N = int(input())
A = [int(i) for i in input().split()]
A.sort()
M = 0
while len(A) != 0:
    if A.count(A[0]) == 1:
        M += 1
        A.remove(A[0])
    else:
        for i in range(A.count(A[0])):
            A.remove(A[0])
print(M)