#include<bits/stdc++.h>
using namespace std;
const int MAXN = 1e5+10;
int cnt[MAXN];
int a[MAXN];
int b[MAXN];
int n,m;
typedef pair<int,int>arr;
priority_queue<arr>q;
int main(){
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;++i){
		scanf("%d",&a[i]);
		q.push(arr(a[i],i));
	}
	for(int i=1;i<=n;++i)scanf("%d",&b[i]);
	int ans=0;
	while(m--&&!q.empty()){
		arr x=q.top();q.pop();
		ans^=x.first;
		cnt[x.second]++;
		if(cnt[x.second]==1)q.push(arr(b[x.second],x.second));
		else if(cnt[x.second]==2)q.push(arr(a[x.second],x.second));
	}
	cout<<ans<<endl;
	return 0;
}