#include<iostream>
#include<vector>
#include<algorithm>

using namespace std;

int main()
{
    int n;
    cin>>n;
    vector<double> v(n);
    int num;
    for(int i=0; i<n; i++) {
        cin>>num;
        v[i]=num;
    }
    sort(v.begin(),v.end());
    if(n%2==0) {
        printf("%.1f\n",(v[n/2-1]+v[n/2])/2.0);
        //cout << (v[n/2-1]+v[n/2])/2 << endl;
    }
    else { printf("%.1f\n",v[n/2]); }
    return 0;
}