use std::io::*;
use std::str::FromStr;
//use std::num;
//use std::cmp;

fn main() {
    let n: usize = read();
    let mut a: Vec<f64> = vec![0.0; n];
    let mut tmp: f64 = 0.0;

    for _i in 0..a.len(){
        a[_i] = read();
    }

    for _j in 0..a.len() - 1{
        for _i in 0..a.len() - 1{
            if a[_i] > a[_i + 1]{
                tmp = a[_i];
                a[_i] = a[_i + 1];
                a[_i + 1] = tmp as f64;
            }
        }
    }
    
    if n % 2 == 1{
        println!("{}",a[(n - 1) / 2])
    }else{
        println!("{}",(a[n / 2 - 1] + a[n / 2]) / 2.0);
    }
}

pub fn upper_lower(x: char) -> char{
    let result: char;

    if x.is_uppercase(){
        result = x.to_ascii_lowercase();
    } else if x.is_lowercase(){
        result = x.to_ascii_uppercase();
    } else {
        result = x;
    }

    result
}

pub fn max(x: isize, y: isize, z: isize) -> isize {
    let result;
    if x >= y && y >= z {
        result = x;
    } else if x >= z && z >= y {
        result = x;
    } else if y >= x && x >= z {
        result = y;
    } else if y >= z && z >= x {
        result = y;
    } else if z >= x && x >= y {
        result = z;
    } else {
        result = z;
    }

    result
}

pub fn min(x: isize, y: isize, z: isize) -> isize {
    let result;
    if x <= y && y <= z {
        result = x;
    } else if x <= z && z <= y {
        result = x;
    } else if y <= x && x <= z {
        result = y;
    } else if y <= z && z <= x {
        result = y;
    } else if z <= x && x <= y {
        result = z;
    } else {
        result = z;
    }

    result
}

pub fn read_line() -> String {
    let mut s: String = String::new();
    std::io::stdin().read_line(&mut s).ok();

    s
}

pub fn read<T: FromStr>() -> T {
    let stdin = stdin();
    let stdin = stdin.lock();
    let token: String = stdin
        .bytes()
        .map(|c| c.expect("failed to read char") as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect();
    token.parse().ok().expect("failed to parse token")
}

pub fn read_array() -> Vec<char> {
    let array: String = read();
    let chars: Vec<char> = array.trim().chars().collect::<Vec<char>>();
    chars
}

pub fn get_data() -> Vec<u64> {
    let mut s: String = String::new();
    std::io::stdin().read_line(&mut s).ok();
    let vec: Vec<u64> = s
        .trim()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect();

    vec
}

pub fn get_chars() -> Vec<char> {
    let mut s: String = String::new();
    std::io::stdin().read_line(&mut s).ok();

    let vec: Vec<char> = s.trim().chars().collect::<Vec<char>>();

    vec
}