fn main() {
	let mut s = String::new();
	std::io::stdin().read_line(&mut s).ok();
	let n: Vec<f64> = s.split_whitespace().flat_map(str::parse).collect();
	println!("{}", (50. * n[0] * (1. + 1. / (0.8 + 0.2 * n[1]))).floor())
}