#define _USE_MATH_DEFINES	//M_PI(π),M_SQRT2(√2)
#include <iostream>			//std::cout, std::cin
#include <string>			//std::string,std::to_string(C++11)
#include <vector>			//std::vector
#include <valarray>			//std::valarray
#include <algorithm>		//std::sort
#include <time.h>			//localtime_s
#include <cstdlib>			//abs
#include <cmath>			//abs,std::pow,sqrt,sin,cos,round,floor,ceil
#include <fstream>			//std::ifstream,std::ofstream
#include <iomanip>			//std::setprecision,std::setw,std::setfill
#include <random>			//std::random(C++11)
#include <numeric>			//std::accumulate
#include <functional>		//std::greater

int main(void) {

	//test用
	//std::ifstream in("test.txt");
	//std::cin.rdbuf(in.rdbuf());

	//const unsigned int MODULO = 1000000007;	//MODULO 10^9+7用

	int N;
	std::cin >> N;
	std::vector<int> A(N, 0);

	for (int i = 0; i < N; i++) {
		std::cin >> A[i];
	}

	std::sort(A.begin(), A.end());
	
	double ans = 0;
	if (N % 2 == 0) {
		ans = (A[N / 2 - 1] + A[N / 2]) / 2.0;
	}
	else {

		ans = A[N / 2];
	}

	std::cout << ans << std::endl;
}