use std::{
    collections::{BTreeSet, HashMap},
    hash::Hash,
};

fn main() {
    proconio::input! {
        n: usize,
        mut a: [u64; n],
    }
    a.sort_unstable();
    let a = if n % 2 == 0 {
        (a[n / 2] + a[n / 2 - 1]) as f64 / 2.
    } else {
        a[n / 2] as f64
    };
    println!("{a}");
}