#include<bits/stdc++.h>
using namespace std;
deque<int> z;
int main ()
{
	double m,y;
	int n,x;
	cin>>n;
	int a[n];
	for(int i=1;i<=n;i++)
	{
		cin>>a[i],z.push_back(a[i]);
		if(a[i]>a[i+1])
		swap(a[i],a[i+1]);
		x=z.size()/2;
		m=a[x];
	}
	y=z.size()%2;
	if(y==0)
	m=(m+a[x+1])/2;
	printf("%.1lf\n",m);
	return 0;
}