#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]);
	}
	return 0;
}

/**************************************************************
	Problem: 1233
	User: zzz
	Language: C++
	Result: Accepted
	Time:13 ms
	Memory:2072 kb
****************************************************************/