#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,n) for(ll i=0;i<n;i++)
constexpr ll MOD = 998244353;
const int MAX_N = 300300;
vector<ll> fac(MAX_N), finv(MAX_N), inv(MAX_N);
void init(){
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for(int i=2;i<MAX_N;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 mcomb(int n, int k){
    if(n<k) return 0;
    if(n<0 || k<0) return 0;
    return fac[n] * (finv[k] * finv[n-k] % MOD) % MOD;
}
ll mperm(int n,int k){
    if(n<k)return 0;
    if(n<0||k<0)return 0;
    return fac[n] * (finv[n-k] % MOD) % MOD;
}


ll modpow(ll a,ll n,ll mod=MOD){
    a%=mod;
    if(n==0)return 1;
    if(n==1)return a%mod;
    if(n%2==0){
        ll res=modpow(a,n/2,mod);
        return (res*res)%mod;
    }
    else{
        return (a*modpow(a,n-1,mod))%MOD;
    }
}

ll sqrtz(ll N){
    ll n=sqrt(N);
    for(ll i=max(1ll,n-5);i<=n+5;i++){
        if(i*i>N)return i-1;
    }
    return n;
}

bool DEB=0;
int main(){
    ll X,Y,Z,K;
    cin>>X>>Y>>Z>>K;
    ll D=X+Y+Z;
    ll an=0;
    init();
    for(ll d=1;d<=D;d++){
        ll zanD=D-d;
        if(DEB)cout<<d<<" "<<zanD<<endl;
        if(zanD<X-1)continue;
        ll res=1;
        res=X;
        res*=mperm(zanD,X-1);
        res%=MOD;
        if(DEB)cout<<1<<":"<<res<<endl;
        ll okY=zanD+1+K-X;
        ll Ynum=max(d-K,0ll);
        ll inY=min(Y,Ynum);
        if(DEB)cout<<"iY"<<inY<<" "<<Ynum<<endl;
        if(inY>0){
            res*=modpow(okY,inY);
            res%=MOD;
        }
        if(DEB)cout<<2<<":"<<res<<endl;
        if(Y>inY){
            res*=mperm(D-X-inY,Y-inY);
            res%=MOD;
        }
        if(DEB)cout<<3<<":"<<res<<endl;
        res*=fac[Z];
        res%=MOD;
        an+=res;
        an%=MOD;
    }

    an*=finv[D];
    an%=MOD;
    cout<<an<<endl;



}