# これはわかる気がする
# 正しい場所と今ある数字をUF.uniteする
# 各groupのsize-1を総和
# なぜなら4個の数字が4個の間違った場所に入っていれば、3個を直せば全部戻る

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 unite(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
 
    def __str__(self):
        return '\n'.join(f'{r}: {m}' for r, m in self.all_group_members().items())

N = int(input())
P = list(map(int, input().split()))
UF = UnionFind(N+1)
for i in range(N):
    UF.unite(P[i], i+1)
    
#from collections import defaultdict
#print(UF.all_group_members())
    
ans = 0
for r in UF.roots():
    # root 0では次の計算は0になるので無視していい
    ans += UF.size(r)-1
print(ans)