#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n,i,j,s;
    cin>>n;
    int m[n];
    for(i=0;i<n;i++){
        cin>>m[i];
    }
    for(i=n-1;i>=1;i--){
        for(j=0;j<i;j++){
            if(m[j]>m[j+1]){
                swap(m[j],m[j+1]);
            }
        }
    }
    if(n%2==0){
        printf("%.1f",1.0*(m[n/2-1]+m[n/2])/2);
    }else{
        printf("%.1f",1.0*m[n/2]);
    }
}
/**************************************************************
	Problem: 1233
	User: wangyiyang
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/