#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define MAXN 100010
int n,m,a[MAXN],b[MAXN];
ll ans=0;
struct nod{
	int val,id,t;
	bool operator <(const nod x)const{
		return val<x.val||val==x.val&&id<x.id;
	}
};
int main(){
	ios::sync_with_stdio(false);
	cin.tie(0),cout.tie(0);
	cin>>n>>m;
	for(int i=1;i<=n;++i) cin>>a[i];
	for(int i=1;i<=n;++i) cin>>b[i];
	priority_queue<nod>spt;
	for(int i=1;i<=n;++i) spt.push({a[i],i,1});
	ll num=0;
	for(int i=1;i<=m;++i){
		if(spt.empty()){ans^=num;continue;}
		nod u=spt.top();spt.pop();
		num+=u.val;
		ans^=num;
		if(u.t==1) spt.push({b[u.id],u.id,2});
		if(u.t==2) spt.push({a[u.id],u.id,3});
	}cout<<ans<<endl;
	return 0;
}