void main() {
	auto ip = readAs!(long[]), N = ip[0], K = ip[1];
	auto A = readAs!(ulong[]);
	ulong res;
	ulong[] c = new ulong[](64);
	foreach(v; A) foreach(i; 0..64) if(v & (1UL << i)) c[i]++;
	
	foreach(i; -1..64) {
		if(i != -1 && !(K & (1UL << i))) continue;
		auto X = K; X &= ~(1UL << i);
		ulong tmp;
		foreach(j; 0..64) {
			auto mask = (1UL << j);
			if(j < i) {
				tmp += max(c[j], N - c[j]) * mask;
			} else if(j == i) tmp += c[j] * mask;
			else {
				if(K & mask) tmp += (N - c[j]) * mask;
				else tmp += c[j] * mask;
			}
		}
		debug tmp.writeln;
		res = max(res, tmp);
	}
	res.writeln;
}

// ===================================

import std.stdio;
import std.string;
import std.functional;
import std.algorithm;
import std.range;
import std.traits;
import std.math;
import std.container;
import std.bigint;
import std.numeric;
import std.conv;
import std.typecons;
import std.uni;
import std.ascii;
import std.bitmanip;
import core.bitop;

T readAs(T)() if (isBasicType!T) {
	return readln.chomp.to!T;
}
T readAs(T)() if (isArray!T) {
	return readln.split.to!T;
}

T[][] readMatrix(T)(uint height, uint width) if (!isSomeChar!T) {
	auto res = new T[][](height, width);
	foreach(i; 0..height) {
		res[i] = readAs!(T[]);
	}
	return res;
}

T[][] readMatrix(T)(uint height, uint width) if (isSomeChar!T) {
	auto res = new T[][](height, width);
	foreach(i; 0..height) {
		auto s = rs;
		foreach(j; 0..width) res[i][j] = s[j].to!T;
	}
	return res;
}

int ri() {
	return readAs!int;
}

double rd() {
	return readAs!double;
}

string rs() {
	return readln.chomp;
}
