#include <bits/stdc++.h>
using namespace std;

//#include <boost/algorithm/string/join.hpp>
//#include <boost/range/irange.hpp>
//#include <boost/multiprecision/cpp_int.hpp>
#include "boost/multi_array.hpp"
//
//using boost::irange;
//using boost::algorithm::join;
//
// boost::multi_array<int, 3> table;
// table.resize(boost::extents[10][9][8]);

typedef long long ll;
typedef unsigned long long ull;
//typedef long double ld;

typedef map<int, int> mii;
typedef pair<int, int> pii;
typedef pair<double,double> pdd;
typedef set<int> si;
typedef set<ll> sll;
typedef vector<int> vi;
typedef vector<pair<int, int > > vii;
typedef vector<ll> vll;
typedef vector<double> vd;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
typedef vector<vll> vvll;

//constexpr ll MOD = 1e9+7;
template<typename T>constexpr auto inf=numeric_limits<T>::max()/4;
constexpr int INF=inf<int>;
constexpr ll LINF=inf<ll>;

#define Sort(x) sort(begin(x),end(x))
#define Reverse(x) reverse(begin(x),end(x))
#define ABS(a,b) ((a)<(b)?(b)-(a):(a)-(b))
#define nbit(n) (1ull<<(n))
#define _ol3(_1,_2,_3,name,...)name
#define _rep(i,n)_repi(i,0,n)
#define _repi(i,a,b)for(int i=a,i##_l=(b);i<i##_l;++i)
#define REP(...) _ol3(__VA_ARGS__,_repi,_rep,)(__VA_ARGS__)
#define REPR(i,n) for(int i=n-1;i>=0;--i)
#define REPA(i,v) REP(i,(v).size())

// sort(begin(x), end(x), greater<ll>());
// lower_bound(a.begin(), a.end(), val): a[i] ≥ valである最左の位置
// upper_bound(a.begin(), a.end(), val): a[i] > valである最左の位置

// Returns minimum of a and b.
// If a is less b, a is set to b.
template<typename T>
T chmin(T& a, T b) {
  if (a > b) {
    a = b;
  }
  return a;
}

// Returns maximum of a and b.
// If a is less b, a is set to b.
template<typename T>
T chmax(T& a, T b) {
  if (a < b) {
    a = b;
  }
  return a;
}

template <typename T>
void dumpContents(const T& v, const string& msg)
{
  cerr << "### " << msg << " ###\n";
  for (const auto& x : v) {
    cerr << x << " ";
  }
  cerr << endl;
}

struct before_main_function {
  before_main_function() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout<<setprecision(20)<<fixed;
#define endl "\n"
  }
} before_main_function;

// ========== end of template ==========
constexpr ull A_MAX = 1e12;
constexpr int DIGIT_MAX = 40; // 2^40 > 1e12

int main(int argc, char** argv) {
  int N;
  ull K;
  cin >> N >> K;

  vector<ull> A(N);
  for (auto& a : A) {
    cin >> a;
  }

  // ads[d] は、A[0],...,A[N-1]において、d桁目の1の総数
  vi ads(DIGIT_MAX);
  {
    vector<ull> tmp = A;
    REP(d, DIGIT_MAX) {
      REP(i, N) {
        ads[d] += tmp[i]%2;
        tmp[i] /= 2;
      }
    }
  }

  boost::multi_array<ll, 2> dp;
  dp.resize(boost::extents[DIGIT_MAX][2]);
  REP(i, DIGIT_MAX) {
    dp[i][1] = -1;
  }

  REP(i, DIGIT_MAX) {
    const int d = DIGIT_MAX - 1 - i; // 上から見る
    int maxk2 = (K>>d) & 1ull;
    int count = 0;

    // 1) exact -> exactは maxk2を採用
    if (maxk2 == 0) {
      // 0のみ -> 1の個数
      count = ads[d];
    } else {
      // 1のみ -> 0の個数
      count = N-ads[d];
    }
    chmax(dp[i][0], (i>0 ? dp[i-1][0] : 0) + ll(nbit(d))*count);

    // 2) exact -> all
    if (maxk2 == 1) {
      // 0のみ -> 1の個数
      count = ads[d];
      chmax(dp[i][1], (i>0 ? dp[i-1][0] : 0) + ll(nbit(d))*count);
    }

    // 3) all -> all
    if (i>0 && dp[i-1][1] >= 0) {
      count = max({ads[d], N-ads[d]});
      chmax(dp[i][1], (i>0 ? dp[i-1][1] : 0) + ll(nbit(d))*count);
    }

cerr << "d " << d;
cerr << "dp " << dp[i][0] << ", " << dp[i][1] << endl;
  }

  ull ret = max({dp[DIGIT_MAX-1][0], dp[DIGIT_MAX-1][1]});
  cout << ret << endl;
  return 0;
}

/* vim: set expandtab shiftwidth=2 softtabstop=2 : */


Measured memory_bytes: 1792