fn main() {
	let mut s = String::new();
	std::io::stdin().read_line(&mut s).ok();
	let c: Vec<_> = s.chars().collect();
	println!(
		"{}",
		if c[0] == c[1] && c[1] != c[2] {
			"Yes"
		} else {
			"No"
		}
	)
}