true = True

false = False

def ii():
    return int(input())

def lmi():
    return list(map(int, input().split()))

n = ii()
a = lmi()
ll = [false for _ in range(n)]
ans = 0
for i in range(n):
    if not ll[i]:
        s = set()
        s.add(i)
        next = a[i] - 1
        ll[i] = true
        while next not in s:
            s.add(next)
            ll[next] = true
            next = a[next] - 1
        ans += 1

print(ans)