#![allow(dead_code, unused_mut)]
#![allow(non_snake_case)]

macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let mut s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};

    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };

    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };

    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };

    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };

    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}

struct Combination {
    MOD: u64,
    size: usize,
    fact: Vec<u64>,
    inv_fact: Vec<u64>,
}

impl Combination {
    fn new(size: usize, _MOD: u64) -> Self {
        let mut fact = vec![1; size + 1];
        let mut inv_fact = vec![1; size + 1];
        for i in 1..size + 1 {
            fact[i] = fact[i - 1] * i as u64 % _MOD;
        }
        inv_fact[size] = Self::modpow(fact[size], _MOD - 2, _MOD);
        for i in (1..size + 1).rev() {
            inv_fact[i - 1] = inv_fact[i] * i as u64 % _MOD;
        }
        Combination {
            MOD: _MOD,
            size,
            fact,
            inv_fact,
        }
    }
    fn modpow(mut x: u64, mut y: u64, m: u64) -> u64 {
        let mut res: u64 = 1;
        while y > 0 {
            if y & 1 > 0 {
                res = res * x % m;
            }
            x = x * x % m;
            y >>= 1;
        }
        res
    }
    fn modinv(x: u64, m: u64) -> u64 {
        Self::modpow(x, m - 2, m)
    }
    fn nPr(&self, n: usize, r: usize) -> u64 {
        if n < r {
            return 0;
        };
        self.fact[n] * self.inv_fact[n - r] % self.MOD
    }
    fn nCr(&self, n: usize, r: usize) -> u64 {
        if n < r {
            return 0;
        };
        self.fact[n] * self.inv_fact[r] % self.MOD * self.inv_fact[n - r] % self.MOD
    }
}

const MOD: u64 = 998244353;

fn main() {
    input!{
        n:usize, m:usize,
        a:usize, b:usize
    }
    let ncr = Combination::new(m + n + 1, MOD);
    let mut ans = 0;
    let t = (n - 1) * a;
    for s in 1..m+1 {
        let l = std::cmp::min(s + b, m);
        if l - s < t {
            break;
        }
        // println!("{} {}", l -s-t+n, n);

        ans = (ans + ncr.nCr(l - s - t + n - 1, n - 1)) % MOD;
    }
    println!("{}", ans * ncr.fact[n] % MOD);
}