use proconio::input;
fn main() {
    input! {
        n:usize,
        mut num:[i64;n],
    }
    num.sort();
    if n % 2 == 0{
        println!("{}", (num[n / 2 - 1] as f64 + num[n / 2] as f64) / 2.0)
    }else{
        println!("{}",num[n / 2]);
    }
}