def func(worlds):
    f = list('0' * (len(worlds)))
    b = 0
    for i in range(len(f)):
        if f[i] == '0':
            b += 1
            m = worlds[i] - 1
            while f[m] != '1':
                f[m] = '1'
                m = worlds[m] - 1
    return b
def func2(worlds):
    a = func(worlds)
    if a == 1:
        a = 0
    return a
n = int(input())
worlds = list(map(int, input().split()))
print(func2(worlds))