use std::cmp::min;

fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();
    let mut x = String::new();
    std::io::stdin().read_line(&mut x).ok();
    let x: usize = x.trim().parse().unwrap();
    let mut a = String::new();
    std::io::stdin().read_line(&mut a).ok();
    let a: usize = a.trim().parse().unwrap();
    let mut b = String::new();
    std::io::stdin().read_line(&mut b).ok();
    let b: usize = b.trim().parse().unwrap();

    let rest = (1 << ((n-1) as usize)) - x;
    let result = rest / b + if rest % b == 0 { 0 } else { 1 };
    let result = min(result as usize, x / a + if x % a == 0 { 0 } else { 1 });
    println!("{}", result);
}