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

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

    def merge(self, x, y):
        rx = self.leader(x)
        ry = self.leader(y)
        if rx == ry: return False
        if self.parent_or_size[rx] > self.parent_or_size[ry]: rx, ry = ry, rx
        self.parent_or_size[rx] += self.parent_or_size[ry]
        self.parent_or_size[ry] = rx
        self.siz -= 1
        return True

N = int(input())
A = list(map(int, input().split()))

uf = UnionFind(N)

for i in range(N):
    uf.merge(i, A[i] - 1)

print(N - uf.siz)