#include<bits/stdc++.h>
using namespace std;
int a[155],n,i,j;
float q;
int main(){
    cin>>n;
    for(i=0;i<n;i++){
        cin>>a[i];
    }
    for(i=n-1;i>0;i--){
        for(j=0;j<i;j++){
            if(a[j]>a[j+1]){
                swap(a[j],a[j+1]);
            }
        }
    }
    if(n%2==1){
        printf("%.1f",a[n/2]*1.0);
    }else{
        printf("%.1f",(a[n/2-1]+a[n/2])*1.0/2);
    }
    return 0;
}
/**************************************************************
	Problem: 1233
	User: lijinkai
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/