#define rep(i, n) for (int i = 0; i < (int)(n); i++) #define ALL(v) v.begin(), v.end() typedef long long ll; #include using namespace std; const ll MAX = 310000; const ll MOD = 998244353; ll fac[MAX], finv[MAX], inv[MAX]; void init(){ fac[0]=fac[1]=1; finv[0]=finv[1]=1; inv[1]=1; for(int i=2;i>n>>m>>a>>b; init(); ll ans=0; for(int i=1;i<=m;i++) ans=(ans+nCr(min(b,m-i)-(n-1)*(a-1),n-1))%MOD; cout<<(ans*nPr(n,n))%MOD<