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

public class No00000275_Main {

	public static void main(String[] args) throws IOException {

		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = Integer.parseInt(br.readLine());
		double[] arr = Stream.of(br.readLine().split(" ")).mapToDouble(Double::parseDouble).toArray();
		Arrays.sort(arr);
		if(n % 2 == 0) {
			System.out.println((arr[(n / 2) - 1] + arr[n / 2]) / 2);
		} else {
			System.out.println(arr[n / 2]);
		}
	}
}