#include<bits/stdc++.h>
using namespace std;
constexpr int mod=998244353;
typedef long long ll;
int main(){
    std::ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    int a,b,c;ll n;cin>>a>>b>>c>>n;
    if(n<=2){cout<<(n==1?a:b)<<'\n';return 0;}n-=3;
    if(!a&&!b&&!c){cout<<"0\n";return 0;}
    int mx=1+__lg(max({a,b,c}));ll z=3<<mx;
    ll ans=0;
    vector<ll> B;
    for(int i=0,pos=n%z,w=(1<<mx+1)-1,ww=w>>1;i<z;i++){
        swap(a,b);b^=a;
        if(i<=n&&c+b>w)B.emplace_back(i);
        b+=c;b&=w;
        if(i==pos)ans=b;
    }int pw=1<<mx;
    while(!B.empty()){
        vector<ll> tmp;
        bool cur=0,a[3]={0,0,0},cnm=0;
        ll pos=n%(z<<1);
        for(ll x:B){
            if(pos<x&&!cnm)cur=a[pos%3],cnm=1;
            if(x>n) break;
            if(a[x%3]) tmp.emplace_back(x);
            a[x%3]^=1;a[(x+1)%3]^=1;
        }
        if(z<=n){
            for(ll x:B){
                x+=z;
                if(pos<x&&!cnm)cur=a[pos%3],cnm=1;
                if(x>n) break;
                if(a[x%3]) tmp.emplace_back(x);
                a[x%3]^=1;a[(x+1)%3]^=1;
            }
            z<<=1;
        }
        pw<<=1;if(pw>=mod)pw-=mod;
        if(!cnm) cur=a[pos%3];
        if(cur) ans+=pw;
        swap(B,tmp);
    }
    cout<<ans%mod<<'\n';
}