num_NewInt = int(input())
Integer = input().split(" ")

"""
for i in range(len(Integer)):
    print(Integer[i])
"""
int_set = set()
for i in range(num_NewInt):
    if Integer[i] not in int_set:
        int_set.add(Integer[i])
    else:
        num_NewInt-=1

print(num_NewInt)
#print(int_set)