import std.stdio, std.conv, std.string;
import std.algorithm, std.array, std.container;
import std.numeric, std.math;
import core.bitop;
 
T RD(T = string)() { static string[] ss; while(!ss.length) ss = readln.chomp.split; string res = ss[0]; ss.popFront; return res.to!T; }
string RDR()() { return readln.chomp; }
 
long mod = pow(10, 9) + 7;
long moda(long x, long y) { return (x + y) % mod; }
long mods(long x, long y) { return ((x + mod) - (y % mod)) % mod; }
long modm(long x, long y) { return (x * y) % mod; }
 
void main()
{
	auto N = RD!ulong;
	auto K = RD!ulong;
	auto A = RDR.split.to!(ulong[]);
 
	ulong[64] bitCnt;
	foreach (e; A)
	{
		foreach (i; 0..64)
		{
			if (e & (cast(ulong)1 << i)) ++bitCnt[i];
		}
	}
 
	ulong x;
	ulong ans;
	foreach_reverse (i; 0..64)
	{
		if (bitCnt[i] > N / 2) continue;
 
		ulong bit = cast(ulong)1 << i;
		if (x + bit <= K) x += bit;
	}
 
	foreach (e; A)
	{
		ans += e ^ x;
	}
 
	writeln(ans);
	stdout.flush();
}