#include"bits/stdc++.h"
using namespace std;
#define REP(k,m,n) for(int (k)=(m);(k)<(n);(k)++)
#define rep(i,n) REP((i),0,(n))
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using tp3 = tuple<int, int, int>;
using Mat = vector<vector<ll>>;
constexpr int INF = 1 << 28;
constexpr ll INFL = 1ll << 60;
constexpr int dh[4] = { 0,1,0,-1 };
constexpr int dw[4] = { -1,0,1,0 };
bool isin(const int H, const int W, const int h, const int w) {
    return 0 <= h && h < H && 0 <= w && w < W;
}

struct ModInt {
    static const ll MOD = 998244353;

    // constructors etc
    ModInt() :num(1ll) {}
    ModInt(ll num_) :num(num_%MOD) {}
    ModInt(const ModInt& modint) :num(modint.num%MOD) {}
    ll get()const { return num; }

    // operator etc
    // operator ll() const { return num; }
    // ll operator*() { return num; }
    ModInt& operator+=(const ModInt& r) { (num += r.num) %= MOD; return *this; }
    ModInt& operator-=(const ModInt& r) { (num += -r.num + MOD) %= MOD; return *this; }
    ModInt& operator*=(const ModInt& r) { (num *= r.num) %= MOD; return *this; }
    ModInt& operator/=(const ModInt& r) { (num *= r.inv().num) %= MOD; return *this; }
    ModInt pow(const ModInt& r)const {
        ll res = 1;
        ll x = num;
        ll n = r.num;
        while (n > 0) {
            if (n & 1)res = (res*x) % MOD;
            x = (x*x) % MOD;
            n >>= 1;
        }
        return res;
    }
    ModInt inv()const { return this->pow(MOD - 2); }

    ModInt operator+(const ModInt& r)const { return ModInt(*this) += r; }
    ModInt operator-(const ModInt& r)const { return ModInt(*this) -= r; }
    ModInt operator*(const ModInt& r)const { return ModInt(*this) *= r; }
    ModInt operator/(const ModInt& r)const { return ModInt(*this) /= r; }
    ModInt operator+(const ll& r)const { return *this + ModInt(r); }
    ModInt operator-(const ll& r)const { return *this - ModInt(r); }
    ModInt operator*(const ll& r)const { return *this * ModInt(r); }
    ModInt operator/(const ll& r)const { return *this / ModInt(r); }

private:
    ll num;
};
ostream& operator<<(ostream& stream, const ModInt& val) { stream << val.get(); return stream; }

struct Comb {
    static constexpr ll LIM = 310000;
    static vector<ModInt> fact, inv;

    static void init() {
        fact.resize(LIM, 1);
        inv.resize(LIM, 1);

        REP(i, 1, LIM)fact[i] = fact[i - 1] * i;
        inv[LIM - 1] = fact[LIM - 1].inv();
        for (ll i = LIM - 2; i > 0; i--)inv[i] = inv[i + 1] * (i + 1);
    }

    static ll comb(ll n, ll k) {
        if (n < k)return 0ll;
        return (fact[n] * inv[k] * inv[n - k]).get();
    }
};
vector<ModInt> Comb::fact;
vector<ModInt> Comb::inv;
// ============ template finished ============

int main()
{
    ll N, M, A, B;
    cin >> N >> M >> A >> B;
    Comb::init();

    ModInt res(0);
    const ll LIM = B - A * (N - 1);
    rep(alpha, LIM + 1) {
        auto tres = Comb::fact[N] * Comb::comb(alpha + N, alpha);
        res += tres;
    }
    cout << res << endl;
    return 0;
}