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

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

    let n: usize = it.next().unwrap().parse().unwrap();
    let w: usize = it.next().unwrap().parse().unwrap();

    let mut x = vec![0_usize; n];
    let mut max_x = 0_usize;
    for v in &mut x {
        *v = it.next().unwrap().parse().unwrap();
        max_x = max_x.max(*v);
    }

    let mut value_sum = vec![0_u64; max_x + 1];
    for &weight in &x {
        let y: u64 = it.next().unwrap().parse().unwrap();
        value_sum[weight] += y;
    }

    let mut ans = 0_u64;
    for d in w..=max_x {
        let mut total = 0_u64;
        let mut multiple = d;
        while multiple <= max_x {
            total += value_sum[multiple];
            multiple += d;
        }
        ans = ans.max(total);
    }

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