#include<bits/stdc++.h>
#define ull unsigned long long 
#define mod 998244353
using namespace std;
const int m=20;
int a,b,c,r[3],ans;
ull n,len;
int main(){
	scanf("%d%d%d%llu",&a,&b,&c,&n);
	if(n==1) return printf("%d",a),0;
	if(n==2) return printf("%d",b),0;
	n-=3;len=(1ll<<(m-1))*3;
	vector<ull > v0;
	for(ull i=0;i<len&&i<=n;i++){
		int d=(a^b)+c;
		if(d>=(1<<m)) d-=(1<<m),v0.push_back(i);
		if(i==n%len) ans=d;
		a=b,b=d;
	}
	int mp=(1<<m);
	while(!v0.empty()){
		vector<ull > v1;
		int t=0;
		for(ull x:v0) t^=(x%3!=(n+1)%3&&((n-x)/len)%2==0);
		if(t){
			ans+=mp;
			if(ans>=mod) ans-=mod;
		}
		mp*=2;
		if(mp>=mod) mp-=mod;
		r[0]=r[1]=r[2]=0;
		for(ull x:v0){
			if(r[x%3]^r[(x+2)%3]) v1.push_back(x);
			r[x%3]^=1;
		}
		for(ull x:v0){
			if((r[x%3]^r[(x+2)%3])&&x+len<=n) v1.push_back(x+len);
			r[x%3]^=1; 
		}
		v0=v1;
		len*=2;
		if(len>n) len=n+1;
	}
	printf("%d",ans);
}