fn main() {
    let _ = read::<u32>();
    let mut a = read_vec::<i32>();
    a.sort();
    let a:Vec<f64> = a.into_iter().map(|n|n as f64).collect();
    if a.len() % 2 == 1 {
        println!("{}", a[a.len()/2]);
    } else {
        println!("{}", (a[a.len()/2]+a[a.len()/2-1])/2f64);
    }
}

fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>().split_whitespace()
        .map(|e| e.parse().ok().unwrap()).collect()
}