from sys import stdin
input=lambda :stdin.readline()[:-1]

from collections import defaultdict

class UnionFind():
  def __init__(self,n):
    self.n=n
    self.parents=[-1]*n

  def find(self,x):
    if self.parents[x]<0:
      return x
    else:
      self.parents[x]=self.find(self.parents[x])
      return self.parents[x]

  def union(self,x,y):
    x=self.find(x)
    y=self.find(y)

    if x==y:
      return

    if self.parents[x]>self.parents[y]:
      x,y=y,x

    self.parents[x]+=self.parents[y]
    self.parents[y]=x

  def size(self,x):
    return -self.parents[self.find(x)]

  def same(self,x,y):
    return self.find(x)==self.find(y)

  def members(self,x):
    root=self.find(x)
    return [i for i in range(self.n) if self.find(i)==root]

  def roots(self):
    return [i for i, x in enumerate(self.parents) if x< 0]

  def group_count(self):
    return len(self.roots())

  def all_group_members(self):
    group_members=defaultdict(list)
    for member in range(self.n):
      group_members[self.find(member)].append(member)
    return group_members

n=int(input())
p=list(map(lambda x:int(x)-1,input().split()))
uf=UnionFind(n)
for i in range(n):
  uf.union(i,p[i])
g=uf.all_group_members()
print(n-len(g))