#include <bits/stdc++.h>

[[nodiscard]] static inline constexpr std::vector<int_least32_t> prepare(const uint_fast32_t N, const std::vector<int_least32_t>& A) noexcept
{
	std::array<uint_least32_t, 2001> count_of = { 0, };
	for (uint_fast32_t i = 0; i != N; ++i)
	{
		[[assume(A[i] >= -1000 && A[i] <= 1000)]];
		++count_of[A[i] + 1000];
	}

	std::vector<int_least32_t> _A(N, 0);
	for (int_fast32_t i = 0, j = 0; i != 2001; ++i)
		while (count_of[i] != 0)
			_A[j] = i - 1000, --count_of[i], ++j;

	return _A;
}

[[nodiscard]] static inline constexpr double solve(const uint_fast32_t N, const std::vector<int_least32_t>& _A) noexcept
{
	[[assume(std::is_sorted(_A.begin(), _A.end()))]];
	if (N & 1) return _A[N / 2];
	else return (_A[N / 2 - 1] + _A[N / 2]) / 2.0;
}

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

	uint_fast32_t N;
	std::cin >> N;
	std::vector<int_least32_t> A(N);
	for (uint_fast32_t i = 0; i != N; ++i)
		std::cin >> A[i];

	std::cout << std::fixed << std::setprecision(10) << solve(N, prepare(N, std::move(A))) << '\n';
	return 0;
}