package jp.co.kokou.sample.no275;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.stream.Stream;

public class Main {

    public static void main(String[] args) {
        try (InputStreamReader isr = new InputStreamReader(System.in);
             BufferedReader br = new BufferedReader(isr)) {

            br.readLine(); // 最初の値は捨てる
            String[] strNums = br.readLine().split("\\s+");
            int[] nums = Stream.of(strNums).mapToInt(Integer::parseInt).toArray();
            System.out.format("%.1f%n", Median.calc(nums));
        } catch (IOException ex) {

        }
    }

    public static class Median {

        public static double calc(int... numbers) {
            int[] nums = Arrays.copyOf(numbers, numbers.length);
            Arrays.sort(nums);
            if (nums.length % 2 == 0) {  // 偶数
                return (nums[nums.length / 2 - 1] + nums[nums.length / 2]) / 2.0;
            } else { // 奇数
                return nums[nums.length / 2];
            }
        }
    }
}