import java.util.Scanner;

class Y275{
    public static void main(String args[]){
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        int[] A=new int[n];
        for(int i=0;i<n;i++){
            A[i]=sc.nextInt();
        }
        for(int i=0;i<n-1;i++){
            for(int j=i+1;j<n;j++){
                if(A[i]>A[j]){
                    int tmp=A[i];
                    A[i]=A[j];
                    A[j]=tmp;
                }
            }
        }
        double ans;
        if(n%2==0){
            ans=(A[n/2-1]+A[n/2])/2.0;
            System.out.print(ans);
        }else{
            System.out.println(A[n/2]);
        }
    }
}