#include <bits/stdc++.h>
using namespace std;
int main(){
	float s;
	int i,n,j;
	cin>>n;
	int a[n];
	for(i=1;i<=n;i++)
	cin>>a[i-1];
	for(i=1;i<=n-1;i++){
		for(j=0;j<n-i;j++){
			if(a[j]>a[j+1])
			swap(a[j],a[j+1]);
	    }
	}
	if(n%2==1)
	    s=a[n/2]*1.0;
    else
        s=(a[n/2]*1.0+a[n/2-1])/2;
    cout<<s;
	return 0;
	}
/**************************************************************
	Problem: 1233
	User: fzy001
	Language: C++
	Result: Wrong Answer
****************************************************************/