#include <iostream>
#include <cstdint>
#include <vector>

static inline constexpr std::vector<bool> prepare(const uint_fast32_t N, const std::vector<uint_fast32_t>& P) noexcept
{
	std::vector<bool> is_master(N + 1, true);
	for (uint_fast32_t i = 1; i <= N; ++i)
		is_master[P[i]] = false;

	return is_master;
}

static inline constexpr uint_fast32_t solve(const uint_fast32_t N, const std::vector<uint_fast32_t>& P) noexcept
{
	const std::vector<bool> is_master = prepare(N, P);
	std::vector<bool> is_target(N + 1, false);
	for (uint_fast32_t i = 1; i <= N; ++i)
		if (is_master[i])
			is_target[P[P[i]]] = true;

	uint_fast32_t ans = 0;
	for (uint_fast32_t i = 1; i <= N; ++i)
		if (is_target[i]) ++ans;

	return ans;
}

int main()
{
	std::cin.tie(nullptr);
	std::ios::sync_with_stdio(false);

	uint_fast32_t N, i;
	std::cin >> N;
	std::vector<uint_fast32_t> P(N + 1);
	for (i = 1; i <= N; ++i)
		std::cin >> P[i];

	std::cout << solve(N, P) << '\n';
	return 0;
}