/* #region Head */

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

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pll = pair<ll, ll>;
template <class T> using vc = vector<T>;
template <class T> using vvc = vc<vc<T>>;
using vll = vc<ll>;
using vvll = vvc<ll>;
using vld = vc<ld>;
using vvld = vvc<ld>;
using vs = vc<string>;
using vvs = vvc<string>;
template <class T, class U> using um = unordered_map<T, U>;
template <class T> using pq = priority_queue<T>;
template <class T> using pqa = priority_queue<T, vc<T>, greater<T>>;
template <class T> using us = unordered_set<T>;

#define REP(i, m, n) for (ll i = (m), i##_len = (ll)(n); i < i##_len; ++(i))
#define REPM(i, m, n) for (ll i = (m), i##_max = (ll)(n); i <= i##_max; ++(i))
#define REPR(i, m, n) for (ll i = (m), i##_min = (ll)(n); i >= i##_min; --(i))
#define REPD(i, m, n, d) for (ll i = (m), i##_len = (ll)(n); i < i##_len; i += (d))
#define REPMD(i, m, n, d) for (ll i = (m), i##_max = (ll)(n); i <= i##_max; i += (d))
#define REPI(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++)
#define ALL(x) begin(x), end(x)
#define SIZE(x) ((ll)(x).size())
#define PERM(c)                                                                                                        \
    sort(ALL(c));                                                                                                      \
    for (bool c##p = 1; c##p; c##p = next_permutation(ALL(c)))
#define UNIQ(v) v.erase(unique(ALL(v)), v.end());

#define endl '\n'
#define sqrt sqrtl
#define floor floorl
#define log2 log2l

constexpr ll INF = 1'010'000'000'000'000'017LL;
constexpr ll MOD = 1'000'000'007LL; // 1e9 + 7
constexpr ld EPS = 1e-12;
constexpr ld PI = 3.14159265358979323846;

template <typename T> istream &operator>>(istream &is, vc<T> &vec) { // vector 入力
    for (T &x : vec) is >> x;
    return is;
}
template <typename T> ostream &operator<<(ostream &os, vc<T> &vec) { // vector 出力 (for dump)
    os << "{";
    REP(i, 0, SIZE(vec)) os << vec[i] << (i == i_len - 1 ? "" : ", ");
    os << "}";
    return os;
}
// ostream &operator<<(ostream &os, vll &vec) { // vector 出力 (for dump)
//     os << "{";
//     REP(i, 0, SIZE(vec)) {
//         if (vec[i] == INF)
//             os << "INF";
//         else if (vec[i] == -INF)
//             os << "-INF";
//         else
//             os << vec[i];
//         os << (i == i_len - 1 ? "" : ", ");
//     }
//     os << "}";
//     return os;
// }
template <typename T> ostream &operator>>(ostream &os, vc<T> &vec) { // vector 出力 (inline)
    REP(i, 0, SIZE(vec)) os << vec[i] << (i == i_len - 1 ? "\n" : " ");
    return os;
}

template <typename T, typename U> istream &operator>>(istream &is, pair<T, U> &pair_var) { // pair 入力
    is >> pair_var.first >> pair_var.second;
    return is;
}
template <typename T, typename U> ostream &operator<<(ostream &os, pair<T, U> &pair_var) { // pair 出力
    os << "(" << pair_var.first << ", " << pair_var.second << ")";
    return os;
}

// map, um, set, us 出力
template <class T> ostream &out_iter(ostream &os, T &map_var) {
    os << "{";
    REPI(itr, map_var) {
        os << *itr;
        auto itrcp = itr;
        if (++itrcp != map_var.end()) os << ", ";
    }
    return os << "}";
}
template <typename T, typename U> ostream &operator<<(ostream &os, map<T, U> &map_var) { return out_iter(os, map_var); }
template <typename T> ostream &operator<<(ostream &os, set<T> &set_var) { return out_iter(os, set_var); }
template <typename T> ostream &operator<<(ostream &os, us<T> &set_var) { return out_iter(os, set_var); }
template <typename T> ostream &operator<<(ostream &os, pq<T> &pq_var) {
    pq<T> pq_cp(pq_var);
    os << "{";
    if (!pq_cp.empty()) {
        os << pq_cp.top(), pq_cp.pop();
        while (!pq_cp.empty()) os << ", " << pq_cp.top(), pq_cp.pop();
    }
    return os << "}";
}

// dump
#define DUMPOUT cerr
void dump_func() { DUMPOUT << endl; }
template <class Head, class... Tail> void dump_func(Head &&head, Tail &&... tail) {
    DUMPOUT << head;
    if (sizeof...(Tail) > 0) DUMPOUT << ", ";
    dump_func(move(tail)...);
}

// chmax (更新「される」かもしれない値が前)
template <typename T, typename U, typename Comp = less<>> bool chmax(T &xmax, const U &x, Comp comp = {}) {
    if (comp(xmax, x)) {
        xmax = x;
        return true;
    }
    return false;
}

// chmin (更新「される」かもしれない値が前)
template <typename T, typename U, typename Comp = less<>> bool chmin(T &xmin, const U &x, Comp comp = {}) {
    if (comp(x, xmin)) {
        xmin = x;
        return true;
    }
    return false;
}

// ローカル用
#define DEBUG_

#ifdef DEBUG_
#define DEB
#define dump(...)                                                                                                      \
    DUMPOUT << "  " << string(#__VA_ARGS__) << ": "                                                                    \
            << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" << endl                                        \
            << "    ",                                                                                                 \
        dump_func(__VA_ARGS__)
#else
#define DEB if (false)
#define dump(...)
#endif

struct AtCoderInitialize {
    static constexpr int IOS_PREC = 15;
    static constexpr bool AUTOFLUSH = false;
    AtCoderInitialize() {
        ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
        cout << fixed << setprecision(IOS_PREC);
        if (AUTOFLUSH) cout << unitbuf;
    }
} ATCODER_INITIALIZE;

string yes = "Yes", no = "No";
// string yes = "YES", no = "NO";
void yn(bool p) { cout << (p ? yes : no) << endl; }

/* #endregion */

/* #region Num */

template <class T> struct Num {
    T x;
    Num(T x) : x(x) {}
    // member function
    Num &operator+=(const Num &another) { return *this = *this + another; }
    Num &operator-=(const Num &another) { return *this = *this - another; }
    Num &operator*=(const Num &another) { return *this = *this * another; }
    Num &operator/=(const Num &another) { return *this = *this / another; }
    Num &operator++() { return *this = *this + 1; }
    Num operator++(int) {
        Num before = *this;
        *this = *this + 1;
        return before;
    }
    Num &operator--() { return *this = *this - 1; }
    Num operator--(int) {
        Num before = *this;
        *this = *this - 1;
        return before;
    }
    Num operator+() const { return *this; }
    Num operator-() const { return Num{-x}; }

    // friend functions
    friend Num operator+(const Num &left, const Num &right) {
        if (abs(left.x) == INF) return Num{left.x};
        if (abs(right.x) == INF) return Num{right.x};
        return Num{left.x + right.x};
    }
    friend Num operator-(const Num &left, const Num &right) { return left + (-right); }
    friend Num operator*(const Num &left, const Num &right) {
        if (abs(left.x) == INF || abs(right.x) == INF) return (left.x == INF ^ right.x == INF) ? Num{-INF} : Num{INF};
        return Num{left.x * right.x};
    }
    friend Num operator/(const Num &left, const Num &right) {
        if (abs(left.x) == INF) return (right.x > 0) ? Num{left.x} : Num{-left.x};
        if (abs(right.x) == INF) return Num{0};
        return Num{left.x / right.x};
    }
    friend bool operator==(const Num &left, const Num &right) { return left.x == right.x; }
    friend bool operator!=(const Num &left, const Num &right) { return left.x != right.x; }
    friend bool operator<(const Num &left, const Num &right) { return left.x < right.x; }
    friend bool operator>(const Num &left, const Num &right) { return left.x > right.x; }
    friend bool operator<=(const Num &left, const Num &right) { return left.x <= right.x; }
    friend bool operator>=(const Num &left, const Num &right) { return left.x >= right.x; }
    friend ostream &operator<<(ostream &os, const Num &obj) {
        if (obj.x == INF)
            os << "INF";
        else if (obj.x == -INF)
            os << "-INF";
        else
            os << obj.x;
        return os;
    }
    friend istream &operator>>(istream &is, Num &obj) {
        is >> obj.x;
        return is;
    }
};

/* #endregion */

// Problem
void solve() {
    ll n, k;
    cin >> n >> k;
    vll a(n);
    cin >> a;

    ll acc = k;
    REP(i, 0, n) acc |= a[i];
    int bitlen = 64 - __builtin_clzll(acc);

    vvll cnt(bitlen, vll(2, 0));
    for (ll ai : a) {
        REP(pos, 0, bitlen) {
            ll digit = (ai >> pos) & 1LL;
            cnt[pos][digit]++;
        }
    }
    using N = Num<ll>;
    vc<vc<vc<N>>> dp(bitlen + 1, vc<vc<N>>(2, vc<N>(2, -INF)));
    dp[bitlen][0][0] = 0;
    REPR(pos, bitlen - 1, 0) {
        ll base = 1LL << pos;
        N prev = *max_element(ALL(dp[pos + 1][0]));
        if ((k >> pos) & 1LL) {
            // 当該bitが立っている
            dp[pos][0][1] = prev + (base * cnt[pos][0]);
            dp[pos][1][0] = prev + (base * cnt[pos][1]);
        } else {
            // 当該bitが立っていない
            dp[pos][0][0] = prev + (base * cnt[pos][1]);
        }
        prev = *max_element(ALL(dp[pos + 1][1]));
        chmax(dp[pos][1][0], prev + (base * cnt[pos][1]));
        chmax(dp[pos][1][1], prev + (base * cnt[pos][0]));
    }
    cout << max(*max_element(ALL(dp[0][0])), *max_element(ALL(dp[0][1]))) << endl;
}

// entry point
int main() {
    solve();
    return 0;
}


Measured memory_bytes: 1276