N = int(input())
f = input()
s_f = f.split()
num = [int(v) for v in s_f]
num.sort()
num.append(pow(10,9) + 1)
num.insert(0,0)
i = 0
for v in range(1, N + 1):
    if num[v - 1] != num[v] and num[v] != num[v + 1]:
        i += 1

print(i)