use std::*;
use io::{stdin, Read};

type IntType = i128;

const MOD: IntType = 998_244_353;

fn add(x: IntType, y: IntType) -> IntType {
    let mut x = x.wrapping_add(y);
    while x < 0 {
        x += MOD;
    }
    while x >= MOD {
        x -= MOD;
    }
    x
}

fn main() {
    let mut n_and_m = String::new();
    stdin().read_line(&mut n_and_m);

    let mut n_and_m: Vec<&str> = n_and_m.trim().split(" ").collect();
    let m = n_and_m.pop().unwrap().parse::<usize>().unwrap();
    let n = n_and_m.pop().unwrap().parse::<usize>().unwrap();
    drop(n_and_m);

    let mut a = vec![b'\0'; n];
    stdin().read(&mut a);
    stdin().read_line(&mut String::new());
    a.reverse();

    let mut b = vec![b'\0'; m];
    stdin().read(&mut b);
    b.reverse();

    let mut pw: IntType = 1;
    let mut res: IntType = 0;
    let mut ans: IntType = 0;
    for (i, b) in b.into_iter().enumerate() {
        if let Some(b'1') = a.get(i) {
            res = add(res, pw);
        }
        if b == b'1' {
            ans = add(ans, res);
        }
        pw = add(pw, pw);
    }
    println!("{}", ans.wrapping_rem_euclid(MOD))
}