#include <iostream>
#include <cmath>
#include <map>

using namespace std;
using lint = long long;

void solve() {
    int n, t;
    cin >> n >> t;

    map<lint, lint> dp{{t, 0}};
    while (n--) {
        lint x;
        cin >> x;

        map<lint, lint> ndp;
        for (auto [t, c] : dp) {
            {
                auto nt = t & x;
                auto nc = c + abs(t - nt);
                ndp[nt] = max(ndp[nt], nc);
            }
            {
                auto nt = t | x;
                auto nc = c + abs(t - nt);
                ndp[nt] = max(ndp[nt], nc);
            }
        }

        swap(dp, ndp);
    }

    lint ans = 0;
    for (auto [t, c] : dp) ans = max(ans, c);
    cout << ans << "\n";
}

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

    solve();

    return 0;
}