#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin>>n;
    int a[105];
    for(int i=0;i<n;i++){
        cin>>a[i];
    }
    for(int i=1;i<=n-1;i++){
        for(int j=0;j<=n-1-i;j++){
            if(a[j+1]<a[j]){
                swap(a[j+1],a[j]);
            }
        }
    }
    if(n%2==0){
        printf("%.1f",(a[n/2]+a[n/2-1])/2.0);
    }
    else{
        printf("%.1f",a[n/2]/1.0);
    }
    return 0;
}
/**************************************************************
	Problem: 1233
	User: luyanchen
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/