#include<stdio.h>
#include<algorithm>
using namespace std;
main(){
    int N;
    int A[1024];
    scanf("%d",&N);
    for(int i = 0;i < N;i++){
        scanf("%d",&A[i]);
    }
    sort(A,A+N);
    double mid;
    if(N % 2 == 0){
        mid = (A[N/2-1] + A[N/2]) / 2.0;
    }else{
        mid = A[N/2];
    }
    printf("%lf\n",mid);
}