кол-во различных эл-лементов

A = []
B = []
l =0
a = int(input())
for  i in range(a):
    A.append(int(input()))
for i in range(a):
    for j in range(len(B)):
        if A[i] == B[j]:
           a -= 1
        l = l + 1
    if l == 0:
        B.append(A[i])
    l = 0
print(a)