class DisjointSetUnion():

    def __init__(self, n):
        self.n = n
        self.par_or_size = [-1] * n
    
    def merge(self, a, b):
        assert(0 <= a < self.n)
        assert(0 <= b < self.n)
        la = self.leader(a)
        lb = self.leader(b)
        if la == lb:
            return la
        if -self.par_or_size[la] < -self.par_or_size[lb]:
            la, lb = lb, la
        self.par_or_size[la] += self.par_or_size[lb]
        self.par_or_size[lb] = la
        return la
    
    def same(self, a, b):
        assert(0 <= a < self.n)
        assert(0 <= b < self.n)
        return self.leader(a) == self.leader(b)
    
    def leader(self, a):
        assert(0 <= a < self.n)
        if (self.par_or_size[a] < 0):
            return a
        else:
            self.par_or_size[a] = self.leader(self.par_or_size[a])
            return self.par_or_size[a]

    def size(self, a):
        assert(0 <= a < self.n)
        return - self.par_or_size[self.leader(a)]

    def group(self):
        result = dict()
        for a in range(self.n):
            la = self.leader(a)
            if la not in result:
                result[la] = []
            result[la].append(a)
        return result


N = int(input())
dsu = DisjointSetUnion(N)
P = list(map(int, input().split()))
for i in range(N):
    dsu.merge(i, P[i] - 1)
g = dsu.group()
print(N - len(g))