#ifdef LOCAL
    #define _GLIBCXX_DEBUG
    #define __clock__
#else
    #pragma GCC optimize("Ofast")
#endif
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using VI = vector<ll>;
using VV = vector<VI>;
using VS = vector<string>;
using PII = pair<ll, ll>;

// tourist set
template <typename A, typename B>
string to_string(pair<A, B> p);

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);

string to_string(const string& s) {
  return '"' + s + '"';
}

string to_string(const char* s) {
  return to_string((string) s);
}

string to_string(bool b) {
  return (b ? "true" : "false");
}

string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}

template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}

template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ")";
}

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}

void debug_out() { cerr << '\n'; }

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif
// tourist set end

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define rep(i,b) FOR(i, 0, b)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<'\n'
#define p2(s, t) cout << (s) << " " << (t) << '\n'
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << '\n'
#define SZ(x) ((int)(x).size())
#define SORT(A) sort(ALL(A))
#define RSORT(A) sort(ALL(A), greater<ll>())
#define MP make_pair
#define p_yes() p("Yes")
#define p_no() p("No")

ll SUM(VI& V){
  return accumulate(ALL(V), 0LL);
}

ll MIN(VI& V){return *min_element(ALL(V));}
ll MAX(VI& V){return *max_element(ALL(V));}

void print_vector(VI& V){
  ll n = V.size();
  rep(i, n){
    if(i) cout << ' ';
    cout << V[i];
  }
  cout << endl;
}

ll gcd(ll a,ll b){
    if(b == 0) return a;
    return gcd(b,a%b);
}

ll lcm(ll a,ll b){
    ll g = gcd(a,b);
    return a / g * b;
}

// long double
using ld = long double;
#define EPS (1e-14)
#define equals(a,b) (fabs((a)-(b)) < EPS)

void no(){p_no(); exit(0);}
void yes(){p_yes(); exit(0);}

const ll mod = 1e9 + 7;
const ll inf = 1e18;
const double PI = acos(-1);

ll ll_pow(ll a, ll n){
    ll ans = 1;
    FOR(i, 0, n){
        ans *= a;
    }
    return ans;
}
// modなし

const int MAX_BIT = 60;
// const int MAX_BIT = 15;

string to_binary(ll a){
  stringstream ss;
  while(a){
    ss << a%2;
    a /= 2;
  }
  rep(i,MAX_BIT) ss<<0;
  string ret = ss.str().substr(0, MAX_BIT);
  reverse(ALL(ret));
  return ret;
}

ll dp[100][2];

void reset(){
  rep(i,100) rep(j,2) dp[i][j]=-1;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    ll N,K;
    cin>>N>>K;

    VI A(N);
    rep(i, N) cin >> A[i];

    // naive
    // ll ma = 0;
    // rep(k,K+1){
    //   ll score = 0;
    //   rep(i,N){
    //     score += k ^ A[i];
    //   }
    //   chmax(ma, score);
    // }
    // p(ma); return 0;

    VS B(N);
    rep(i,N){
      B[i] = to_binary(A[i]);
      debug(B[i]);
    }

    string s = to_binary(K);
    debug(s);

    reset();
    dp[0][0] = 0;
    dp[0][1] = 0;
    
    rep(i, MAX_BIT){
      debug(i);
      ll one=0;
      ll zero=0;
      ll scale = ll_pow(2, MAX_BIT-i-1);
      rep(j,N){
        if(B[j][i]=='0'){
          zero++;
        }else{
          one++;
        }
      }

      // smaller -> smaller
      if(K>=scale){
        if(dp[i][1]!=-1){
          chmax(dp[i+1][1], dp[i][1] + max(one,zero) * scale);
        }
      }else{
        // 選択肢なしにK側は0しか選べない
        //chmax(dp[i+1][1], dp[i][1] + one * scale);
      }

      // fixed -> smaller
      // 0側を選ぶので、Bの1の数だけスコアが入る
      if(s[i]=='1'){
        debug(one);
        chmax(dp[i+1][1], dp[i][0] + one * scale);
      }

      // fixed -> fixed
      if(s[i]=='0'){
        chmax(dp[i+1][0], dp[i][0] + one * scale);
      }else{
        chmax(dp[i+1][0], dp[i][0] + zero * scale);  
      }


      debug(dp[i+1][0], dp[i+1][1]);
    }

    ll ans = max(dp[MAX_BIT][0], dp[MAX_BIT][1]);
    p(ans);
    
    return 0;
}

Measured memory_bytes: 11264