#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#include <vector>
#include <algorithm>
#include <cmath>
#include <queue>
#include <deque>
#include <list>
#include <unordered_map>
#include <unordered_set>
#include <iomanip>
#include <set>
#include <map>
#include <ctime>
#include <stack>
#include <functional>
#include <cstdio>
#include <string>
#include <iostream>
#include <limits>
#include <stdexcept>
#include <numeric>
#include <fstream>
#include <chrono>
#include <utility>
#include <cassert>
#include <random>
#include <time.h>
#include <bitset>
using namespace std;
#define overload4(_1, _2, _3, _4, name, ...) name
#define rep0(a) for (ll _ = 0; _ < ll(a); ++_)
#define rep1(i, n) for (ll i = 0; i < ll(n); ++i)
#define rep2(i, s, n) for (ll i = ll(s); i < ll(n); ++i)
#define rep3(i, s, n, d) for(ll i = ll(s); i < ll(n); i+=d)
#define rep(...) overload4(__VA_ARGS__,rep3,rep2,rep1,rep0)(__VA_ARGS__)
#define rrep0(a) for (ll _ = (a)-1; _ >= ll(0); -- _)
#define rrep1(i, n) for (ll i = ll(n)-1; i >= 0; i--)
#define rrep2(i, n, t) for (ll i = ll(n)-1; i >= (ll)t; i--)
#define rrep3(i, n, t, d) for (ll i = ll(n)-1; i >= (ll)t; i-=d)
#define drep(...) overload4(__VA_ARGS__,rrep3,rrep2,rrep1,rrep0)(__VA_ARGS__)
typedef long long ll;
typedef unsigned long long ull;
typedef long double LD;
typedef double D;
typedef pair<ll,ll> P;
typedef map<ll,ll> M;
// /*
#include <atcoder/all>
using namespace atcoder;
//using namespace internal;
using mint =modint998244353;
//using mint =modint1000000007;
//using mint=static_modint<4649>;
#define ip(x) atcoder::internal::is_prime_constexpr(x)
istream &operator>>(istream &is, mint &a) { int v; cin >> v; a = v; return is; }
ostream &operator<<(ostream &os, const mint &a) { return os << a.val(); }
auto v_pow(ll n,ll base){vector<mint> v(n,1);rep(i,n-1){v[i+1]*=base*v[i];}return v;}
// */
template<typename T> istream &operator>>(istream &is, vector<T> &v) { for (auto &e : v) is >> e; return is; }
template<typename T> ostream &operator<<(ostream &os, const vector<T> &v) { for (auto &e : v) os << e << ' '; return os; }
template<class S, class T>
istream &operator>>(istream &is, pair<S, T> &p) { return is >> p.first >> p.second; }
template<class S, class T>
ostream &operator<<(ostream &os, const pair<S, T> &p) { return os << '{' << p.first << ", " << p.second << '}'; }
template<class S, class T, class U>
istream &operator>>(istream &is, tuple<S, T, U> &t) { return is >> get<0>(t) >> get<1>(t) >> get<2>(t); }
template<class S, class T, class U>
ostream &operator<<(ostream &os, const tuple<S, T, U> &t) {return os << '{' << get<0>(t) << ", " << get<1>(t) << ", " << get<2>(t) << '}';}
#define YES(n) cout << ((n) ? "YES" : "NO"  ) << endl
#define Yes(n) cout << ((n) ? "Yes" : "No"  ) << endl
template <typename F>
ll binary_search(F check,ll ok,ll ng) {
/*binary_search(bool_func,okな値,ngな値)*///しっかり区間内に...
assert(check(ok));
while(abs(ok-ng)>1){
auto x=(ng+ok)/2;
tie(ok,ng)=(check(x)?make_pair(x, ng):make_pair(ok, x));
}
return ok;
}
template <typename F>
double binary_search_real(F check,double ok,double ng,ll iter = 100) {
rep(iter) {
double x=(ok+ng)/2;
tie(ok,ng)=(check(x)?make_pair(x,ng):make_pair(ok,x));
}
return (ok+ng)/2;
}
void tatananonano() {
ios::sync_with_stdio(false);
std::cin.tie(nullptr);
cout<< fixed << setprecision(10);
}
#define LL(...) ll __VA_ARGS__; IN(__VA_ARGS__)
#define INT(...) int __VA_ARGS__; IN(__VA_ARGS__)
#define STR(...) string __VA_ARGS__; IN(__VA_ARGS__)
#define CHR(...) char __VA_ARGS__;IN(__VA_ARGS__)
#define LDL(...) LD __VA_ARGS__;IN(__VA_ARGS__)
#define vv(type, name, h, ...) \
vector<vector<type>> name(h, vector<type>(__VA_ARGS__))
#define vvv(type, name, h, w, ...)   \
vector<vector<vector<type>>> name( \
h, vector<vector<type>>(w, vector<type>(__VA_ARGS__)))
//#define MINT(...) mint __VA_ARGS__;IN(__VA_ARGS__)
template <class T> void scan(T &a) { cin >> a; }
void IN() {}
template <class Head, class... Tail> void IN(Head &head, Tail &...tail) {scan(head);IN(tail...);}
#define overload2(_1, _2, _3,name, ...) name
#define out1(x) cout<<x<<'\n'
#define out2(x,y) cout<<x<<" "<<y<<'\n'
#define out3(x,y,z) cout<<x<<" "<<y<<" "<<z<<'\n'
#define out4(x,y,z,w) cout<<x<<" "<<y<<" "<<z<<" "<<w<<'\n'
#define out(...) overload4(__VA_ARGS__,out4,out3,out2,out1)(__VA_ARGS__)
#define print1(x) cout<<x<<'\n'
#define print2(x,n) cout<<fixed<<setprecision(n)<<x<<endl
#define print3(x,n,empty) cout<<fixed<<setprecision(n)<<x<<" "
#define print(...) overload2(__VA_ARGS__,print3,print2,print1)(__VA_ARGS__)
#define bool_print(x,y1,y2) cout<<(x?y1:y2)<<'\n';
#define all(x) (x).begin(),(x).end()
#define MAX(a) *max_element(all(a));
#define MIN(a) *min_element(all(a));
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define len(x) ll(x.size())
#define uni(x) sort(all(x));x.erase(unique(all(x)),x.end())
#define TFU(s) transform(all(s),begin(s),::toupper);//大文字にする
#define TFL(s) transform(all(s),begin(s),::tolower);//小文字にする
#define replace(s,a,A) replace(s,'a','A')//str(s)のaをAにする
#define ROT(s,i) rotate(s.begin(),s.begin()+i,s.end())//sのi番目から後ろを前にする
#define PQ priority_queue
#define PQD PQ<P,vector<P>,greater<P>>//小さい順
#define PQS PQ<ll,vec,greater<ll>>
#define fi first
#define se second
#define bit(n,k) ((n>>k)&1LL)
#define popcount(n) __builtin_popcountll(n)
template<class T> inline bool chmax(T& a,T b){if(a < b){a=b;return 1;}return 0;}
template<class T> inline bool chmin(T& a,T b){if(a > b){a=b;return 1;}return 0;}
bool in_rect(ll i,ll j,ll h,ll w) {return 0 <= i and i < h and 0 <= j and j < w;}
typedef vector<ll> vec;
typedef vector<string> vs;
typedef vector<vec> mat;
const ll mod = 998244353;
//const ll mod = 1000000007;
const auto INF = (1LL<<(60));
template <typename T, typename U>
T ceil(T x, U y) {return (x > 0 ? (x + y - 1) / y : x / y);}
template <typename T, typename U>
T floor(T x, U y) {return (x > 0 ? x / y : (x - y + 1) / y);}




constexpr ll MAX = 400000;
ll fac[MAX],finv[MAX],inv[MAX];
void cominit(){
fac[0]=fac[1]=1;
finv[0]=finv[1]=1;
inv[1]=1;
for(int i=2;i<MAX;i++){
fac[i]=fac[i-1]*i%mod;
inv[i]=mod-inv[mod%i]*(mod/i)%mod;
finv[i]=finv[i-1]*inv[i]%mod;
}
}

// ll binom(ll n,ll k){
// if(n<k) return 0;
// if(n<0||k<0) return 0;
// return fac[n]*(finv[k]*finv[n-k]%mod)%mod;
// }
ll POM(ll n,ll k){
if(n<k) return 0;
return fac[n]*finv[n-k]%mod;
}
mint binom(ll n,ll k){
if(n<k) return 0;
if(n<0||k<0) return 0;
mint ret=finv[k];
ret*=fac[n];
ret*=finv[n-k];
return ret;
}



int main(){
tatananonano();
cominit();
LL(n,m,a,b);
//if(a*(n-1)>b){cout<<0<<endl;return 0;}
mint ans=0;
rep(x,0,b-a*(n-1)+1){
    ans+=(m-x-a*(n-1))*binom(n+x-2,n-2);
}
ans*=POM(n,n);
cout<<ans<<endl;

}