const MOD: usize = 998244353;

fn power(base: usize, times: usize) -> usize {
    if times == 0 { return 1usize; }
    if times == 1 { return base; }
    let temp = power(base, times/2);
    temp * temp % MOD * power(base, times%2) % MOD
}

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

    if m > n {
        println!("0");
        return;
    }
    let mut total = power(2, n)-1;
    let mut nums = 1usize;
    let mut denoms = 1usize;
    for i in 1..m {
        nums *= (n+1-i) % MOD;
        nums %= MOD;
        denoms *= power(i, MOD-2);
        denoms %= MOD;
        total = MOD + total - nums * denoms % MOD;
    }
    println!("{}", total % MOD);
}