use std::io::Read;

fn main() {
	let mut s = String::new();
	std::io::stdin().read_to_string(&mut s).ok();
	let v: Vec<u64> = s.split_whitespace().flat_map(str::parse).collect();
	println!(
		"{}",
		if v[1] < v[2] && v[1] < v[3] || v[1] > v[2] && v[1] > v[3] {
			"Yes"
		} else {
			"No"
		}
	)
}