use std::collections::*;
use std::io::Write;

type Map<K, V> = BTreeMap<K, V>;
type Set<T> = BTreeSet<T>;
type Deque<T> = VecDeque<T>;

fn main() {
    input! {
        n: usize,
        p: [(i64, i64, i64, i64); n],
    }
    let mut l = CHT::new(p.iter().map(|p| (-p.2, -p.0)).collect());
    let mut r = CHT::new(p.iter().map(|p| (p.2, p.0)).collect());
    let mut d = CHT::new(p.iter().map(|p| (-p.3, -p.1)).collect());
    let mut u = CHT::new(p.iter().map(|p| (p.3, p.1)).collect());
    let mut x = vec![0f64];
    x.extend(l.enumerate());
    x.extend(r.enumerate());
    x.extend(d.enumerate());
    x.extend(u.enumerate());
    x.sort_by(|a, b| a.partial_cmp(b).unwrap());
    x.retain(|x| *x >= 0f64);
    let mut ans = std::f64::MAX;
    for x in x {
        ans = ans.min((r.find(x) + l.find(x)) * (u.find(x) + d.find(x)));
    }
    println!("{:.10}", ans);
}

// max cht
struct CHT {
    po: usize,
    line: Vec<(i64, i64)>, // (a, b) ax + b
}

impl CHT {
    fn new(mut line: Vec<(i64, i64)>) -> Self {
        line.sort();
        line.dedup_by(|a, b| a.0 == b.0);
        let mut stack = vec![line[0]];
        for &(a, b) in line[1..].iter() {
            while stack.len() >= 2 {
                let len = stack.len();
                let (c, d) = stack[len - 1];
                let (e, f) = stack[len - 2];
                //if (d - b) / (a - c) <= (
                if (d - b) * (a - e) <= (f - b) * (a - c) {
                    stack.pop();
                } else {
                    break;
                }
            }
            stack.push((a, b));
        }
        Self { line: stack, po: 0 }
    }
    fn find(&mut self, x: f64) -> f64 {
        let find = |k: usize| -> f64 {
            let (a, b) = self.line[k];
            a as f64 * x + b as f64
        };
        while self.po + 1 < self.line.len() && find(self.po) <= find(self.po + 1) {
            self.po += 1;
        }
        find(self.po)
    }
    fn enumerate(&self) -> Vec<f64> {
        self.line.windows(2).map(|line| {
            let (a, b) = line[0];
            let (c, d) = line[1];
            (b - d) as f64 / (c - a) as f64
        }).collect()
    }
}

// ---------- begin input macro ----------
// reference: https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
#[macro_export]
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

#[macro_export]
macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

#[macro_export]
macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, bytes) => {
        read_value!($iter, String).bytes().collect::<Vec<u8>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}
// ---------- end input macro ----------

warning: unused import: `std::io::Write`
 --> answer.code:2:5
  |
2 | use std::io::Write;
  |     ^^^^^^^^^^^^^^
  |
  = note: `#[warn(unused_imports)]` on by default

error[E0506]: cannot assign to `self.po` because it is borrowed
  --> answer.code:64:13
   |
59 |         let find = |k: usize| -> f64 {
   |                    ----------------- `self.po` is borrowed here
60 |             let (a, b) = self.line[k];
   |                          --------- borrow occurs due to use in closure
...
63 |         while self.po + 1 < self.line.len() && find(self.po) <= find(self.po + 1) {
   |                                                ---- borrow later used here
64 |             self.po += 1;
   |             ^^^^^^^^^^^^ `self.po` is assigned to here but it was already borrowed

error: aborting due to previous error; 1 warning emitted

For more information about this error, try `rustc --explain E0506`.