#include<bits/stdc++.h>
using namespace std;
constexpr int mod=998244353;
typedef long long ll;
constexpr int N=1e7+5;
ll yanami[N],anna[N],*f=yanami,*g=anna,*fs=yanami,*gs=anna;
main(){
    int a,b,c;ll n;cin>>a>>b>>c>>n;
    if(n<=2)return cout<<(n==1?a:b)<<'\n',0;n-=3;
    int mx=1<<1+__lg(max({a,b,c}));ll z=3*mx,ans=0;
    for(int i=0,pos=n%z,w=mx*2-1;i<z;i++){
        swap(a,b);b=(b^a)+c;
        if(i<=n&&b>w)*(f++)=i;b&=w;
        if(i==pos)ans=b;
    }
    while(fs!=f){
        bool cur=0,a[3]={0,0,0},cnm=0;
        ll pos=n%(z<<1);g=gs;
        for(auto i=fs;i!=f;i++){
            const ll x=*i;
            if(!cnm&&pos<x)cur=a[pos%3],cnm=1;
            if(a[x%3]) *(g++)=x;
            a[x%3]^=1;a[(x+1)%3]^=1;
        }
        if(z<=n){
            for(auto i=fs;i!=f;i++){
                const ll x=*i+z;
                if(x>n) break;
                if(!cnm&&pos<x)cur=a[pos%3],cnm=1;
                if(a[x%3])*(g++)=x;
                a[x%3]^=1;a[(x+1)%3]^=1;
            }
            z<<=1;
        }
        mx<<=1;if(mx>=mod)mx-=mod;
        if(!cnm) cur=a[pos%3];
        if(cur) ans+=mx;
        swap(f,g),swap(fs,gs);
    }
    cout<<ans%mod<<'\n';
}