import java.util.Scanner;
import java.util.Arrays;

public class Exercises8{
  public static void main (String[] args){

    Scanner sc = new Scanner(System.in);

    int numLength = sc.nextInt();

    int[] numArray = new int[numLength];

    for (int n = 0; n < numLength; n++){
      numArray[n] = sc.nextInt();
    }
    
    Arrays.sort(numArray);

    float middle;
    if (numLength % 2 == 0){
      middle = ((float)numArray[numLength / 2] + (float)numArray[numLength / 2 - 1]) / 2;
    }else{
      middle = (float)numArray[numLength / 2];
    }

    System.out.println(middle);
  }
}