fn main() {
	let mut xy = String::new();
	std::io::stdin().read_line(&mut xy).ok();
	let mut xy: Vec<i32> = xy.trim().split_whitespace()
		.map(|e| e.parse().unwrap()).collect();

	let ans = 
		if xy[0] == xy[1] { 0 }
		else if xy[0] == 0 { 2 }
		else if xy[1] == 0 { 1 }
		else if xy[0] == -xy[1] { 3 }
		else { -1 };

	println!("{}", ans);
}