#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;
int main() {
	string buffer;
	cin >> buffer;
	char* end;
	int numberOfNumbers = strtol(buffer.c_str(), &end, 10);
	vector<int> numbers;
	for (auto i = 0; i != numberOfNumbers; ++i) {
		cin >> buffer;
		numbers.push_back(strtol(buffer.c_str(), &end, 10));
	}
	sort(numbers.begin(), numbers.end());
	int centerIndex = numbers.size() / 2;
	cout<<(numberOfNumbers % 2 == 1 ? numbers.at(centerIndex) : (numbers.at(centerIndex - 1) + numbers.at(centerIndex)) / 2.0)<<endl;
	return 0;
}