fn main() { let mut input = String::new(); std::io::Read::read_to_string(&mut std::io::stdin(), &mut input).ok(); let input: Vec = input .split_whitespace() .take(2) .map(|n| n.parse().unwrap()) .collect(); println!("{}", u64::from(input[1]) * 2u64.pow(input[0] - 3)); }