use std::io::{self, Read};
use std::str::FromStr;

fn main() {
    let mut input = String::new();
    io::stdin().read_to_string(&mut input).unwrap();

    let mut iter = input.split_whitespace();
    let n: usize = iter.next().unwrap().parse().unwrap();
    let h: i64 = iter.next().unwrap().parse().unwrap();

    let a: Vec<i64> = (0..n)
        .map(|_| iter.next().unwrap().parse().unwrap())
        .collect();
    let b: Vec<i64> = (0..n)
        .map(|_| iter.next().unwrap().parse().unwrap())
        .collect();

    let mut s: Vec<i64> = vec![0; n + 1];
    for i in 0..n {
        s[i + 1] = s[i] + b[i];
    }

    let mut ans = 0;
    let mut tmp = 0;
    let mut need_hp = 0;
    let mut r = 0;
    for l in 0..n {
        while r < n && need_hp + b[r] * (r as i64 - l as i64 + 1) <= h {
            tmp += a[r];
            need_hp += b[r] * (r as i64 - l as i64 + 1);
            r += 1;
        }

        // println!("{} {} {} {}", l, r, need_hp, tmp);
        if tmp > ans {
            ans = tmp;
        }

        if l == r {
            r += 1;
        } else {
            tmp -= a[l];
            need_hp -= s[r] - s[l];
        }
    }

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