fn main() {
    let n: usize = input_line()[0];
    let mut a: Vec<i32> = input_line();

    a.sort();
    if a.len() % 2 != 0 {
        println!("{}", a[n / 2]);
        return;
    }

    println!("{}", (a[n / 2 - 1] + a[n / 2]) as f64 / 2.0);
}

#[allow(unused)]
fn input_line<T: std::str::FromStr>() -> Vec<T> {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}