#include <bits/stdc++.h>
#define rep(i,l,n) for(int i=l;i<n;i++)
#define rer(i,l,n) for(int i=l;i<=n;i++)
#define all(a) a.begin(),a.end()
#define o(a) cout<<a<<endl
#define pb(a) push_back(a)
#define mk(a,b) make_pair(a,b)
#define fi first
#define se second
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pii;

int main(){
	int n;
	cin>>n;
	vector<double> a(n);
	rep(i,0,n) cin>>a[i];
	sort(all(a));
	if(n%2) o(a[n/2]);
	else printf("%.1lf",(a[n/2]+a[n/2-1])*0.5);
}