/*
 *   Copyright (c) 2024 Emon Thakur
 *   All rights reserved.
 */
#include<bits/stdc++.h>
using namespace std;
using ll=long long;
int main()
{
    ll n,k; cin>>n>>k;
    ll a[n];
    for(int i=0;i<n;i++) cin>>a[i];

    ll bit=0;
    for(int j=0;j<60;j++)
    {
        int on=0,off=0;
        for(int i=0;i<n;i++)
        {
            if((a[i]&(1ll<<j))==0) ++off;
            else ++on;
        }
        if((bit | (1ll<<j)) > k) break;
        if(off>=on) bit |= (1ll<<j);
    }

    ll sum = 0;
    for(int i=0;i<n;i++) sum += (a[i]^bit);
    cout<<sum<<endl;
}