use std::io::{self, BufReader, BufWriter, Read, Write};

fn main() {
    let stdin = io::stdin();
    let mut stdin = BufReader::new(stdin.lock());
    let stdout = io::stdout();
    let mut stdout = BufWriter::new(stdout.lock());

    let n = read_usize(&mut stdin);
    let mut a: Vec<i32> = (0..n).map(|_| read_i32(&mut stdin)).collect();
    a.sort();

    if n % 2 == 0 {
        let i = n / 2;
        let avg = (a[i - 1] + a[i]) as f64 / 2.0;
        writeln!(&mut stdout, "{}", avg).unwrap();
    } else {
        writeln!(&mut stdout, "{}", a[n / 2]).unwrap();
    }
}

fn read_usize<R: Read>(reader: &mut R) -> usize {
    reader
        .bytes()
        .filter_map(|b| b.ok())
        .skip_while(|b| b.is_ascii_whitespace())
        .take_while(|b| !b.is_ascii_whitespace())
        .map(|b| b as usize - 48)
        .fold(0, |acc, x| acc * 10 + x)
}

fn read_i32<R: Read>(reader: &mut R) -> i32 {
    let mut iter = reader
        .bytes()
        .filter_map(|b| b.ok())
        .skip_while(|b| b.is_ascii_whitespace())
        .take_while(|b| !b.is_ascii_whitespace());

    let buf = iter.next().unwrap();
    if buf == b'-' {
        iter.map(|b| b as i32 - 48).fold(0, |acc, x| acc * 10 - x)
    } else {
        iter.map(|b| b as i32 - 48)
            .fold(buf as i32 - 48, |acc, x| acc * 10 + x)
    }
}