#include<bits/stdc++.h>
#define int long long
using namespace std;
const int mn=100005,mm=1e6+5;
int n,m,a[mn],b[mn];
int f[mm],fa[mm],fb[mm],ans;
signed main()
{
    scanf("%lld%lld",&n,&m);
    for(int i=1;i<=n;i++)
    {
        scanf("%lld",&a[i]);
    }
    for(int i=1;i<=n;i++)
    {
        scanf("%lld",&b[i]);
        b[i]+=a[i];
    }
    sort(a+1,a+n+1,greater<int>());
    sort(b+1,b+n+1,greater<int>());
    for(int i=1;i<=m;i++)
    {
        if(i>3*n)f[i]=f[i-1];
        else
        {
            if(i==1)
            {
                f[i]=f[i-1]+a[i];
                fa[i]=2;
                fb[i]=1;
            }
            else
            {
                if(fb[i-2]>n || f[i-1]+a[fa[i-1]]>f[i-2]+b[fb[i-2]])
                {
                    f[i]=f[i-1]+a[fa[i-1]];
                    fa[i]=fa[i-1]+1;
                    fb[i]=fb[i-1];
                }
                else
                {
                    f[i]=f[i-2]+b[fb[i-2]];
                    fa[i]=fa[i-2];
                    fb[i]=fb[i-2]+1;
                }
            }
        }
        ans^=f[i];
    }
    printf("%lld",ans);
}