#include<iostream>
#include<algorithm>
using namespace std;
int main()
{
    int n;
    __int64 d[250001];
    scanf("%ld",&n);
    for(int i=0;i<n;i++) {
        scanf("%ld",&d[i]);
    }
    sort(&d[0],&d[n]);
    if(n%2) {
        //cout<<d[(n-1)/2]<<endl;
        printf("%.1f\n",d[(n-1)/2]);
    }
    else
    {
        printf("%.1f\n",((d[(n/2-1)]+d[(n)/2])/2.0));
    }
}