#include<bits/stdc++.h>
using namespace std;
using ll = long long;

#include<atcoder/modint>
using mint = atcoder::modint998244353;

const int mx = 3<<17;
mint fac[mx+1],ifac[mx+1];
int main(){
    fac[0] = 1;
    for(int i = 1;i<=mx;i++) fac[i] = fac[i-1] * mint::raw(i);
    ifac[mx] = fac[mx].inv();
    for(int i = mx-1;i>=0;i--) ifac[i] = ifac[i+1] * mint::raw(i+1);
    int x,y,z,k;
    cin>>x>>y>>z>>k;
    int all = x + y + z;
    int ni = 1;
    mint ans = 0;
    while(true){
        int die = ni + k + 1;
        int can = y + z;
        if(die-1>can) break;
        int left = ni - y;
        left = max(left,0);
        if(left>z) break;
        mint tmp = ifac[all] * fac[all-(die-1)];
        tmp *= fac[z] * ifac[z-left];
        int use = ni - left;
        assert(use<=y);
        int res = z - left + 1;
        res += y - use;
        assert(res-1>=0);
        tmp *= mint::raw(res).pow(use) - mint::raw(res-1).pow(use);
        int r = y + z - use - left;
        assert(r>=k);
        int used = left + use;
        int will = die - 1 - used;
        tmp *= fac[r] * ifac[r-will];
        ans += tmp;
        ni++;
    }
    ans = 1 - ans;
    cout<<ans.val()<<endl;
}