#include <bits/stdc++.h>
#define endl '\n'
#define F first
#define S second
using namespace std;
#define ll long long
#define pb push_back
#define mod 1000000007
#define int long long
#define all(x)      x.begin(),x.end()
#define allr(x)     x.rbegin(),x.rend()
#define CheckBit(x,k)   (x & (1LL << k))
#define SetBit(x,k)     (x |= (1LL << k))
#define ClearBit(x,k)   (x &= ~(1LL << k))
#define LSB(mask)       __builtin_ctzll(mask)
#define MSB(mask)       63-__builtin_clzll(mask) 
#define print(x)    cout << #x << " : " << x << endl
#define error1(x)   cerr << #x << " = " << (x) <<endl
#define coutall(v)  for(auto &it: v) cout<<it<<' '; cout<<endl
#define Abid_52     ios::sync_with_stdio(false);cin.tie(0),cin.tie(0)
#define error2(a,b) cerr<<"( "<<#a<<" , "<<#b<<" ) = ( "<<(a)<<" , "<<(b)<<" )\n"
#define UNIQUE(x)   sort(all(x)), x.erase(unique(all(x)), x.end()), x.shrink_to_fit()
template <typename T, typename U> T ceil(T x, U y) {return (x > 0 ? (x + y - 1) / y : x / y);}
template <typename T, typename U> T floor(T x, U y) {return (x > 0 ? x / y : (x - y + 1) / y);}

const int N = 1e5 + 10;

void solve()
{
    int n, m;
    cin >> n >> m;
    vector<int> v(n + 5);
    for (int i = 0; i < n; i++)
    {
        cin >> v[i];
    }
    // ll mx=0;
    // for(int i=0;i<=m;i++)
    // {
    //     ll ans=0;
    //     for(int j=0;j<n;j++)
    //     {
    //         ans+=(v[j]^i);
    //     }
    //     mx=max(ans,mx);
    //     if(ans==131264)print(i);
    // }
    // print(mx);
    vector<int>zero(45,0);
    for (int j = 0; j < n; j++)
    {
        for (int i = 44; i >= 0; i--)
        {
            if(!CheckBit(v[j],i))
            {
                zero[i]++;
            }
        }
    }
    ll val=0;
    for(int i=44;i>=0;i--)
    {
        if(zero[i]>n/2 && (1ll<<i)<=m)
        {
            val+=(1ll<<i);
            m-=(1ll<<i);
        }
    }
    ll ans=0;
    for(int i=0;i<n;i++)
    {
        ans+=(v[i]^val);
    }
    cout<<ans<<endl;
}

int32_t main()
{
    Abid_52;
    int t = 1;
    // cin >> t;
    for (int tc = 1; tc <= t; ++tc)
    {
        // cout << "Case " << tc << ": ";
        solve();
    }
}