#include<bits/stdc++.h>
using namespace std;
typedef unsigned long long ull;
int n,ans,tmp;
ull a[200000],b;
ull dp[1<<20];
int main(){
	cin>>n>>b;
	if(n>20)
		return 0;
	for(int i=0;i<n;i++)
		cin>>a[i];
	dp[0]=b;
	for(int S=1;S<1<<n;S++)
		dp[S]=-1;
	int ans=0;
	for(ull S=0;S<1<<n;S++){
		if(dp[S]==-1)
			continue;
		ans=max(ans,popcount(S));
		for(int i=0;i<n;i++)
			if(~S>>i&1&&dp[S]>=a[i])
				dp[S|1<<i]=dp[S]^a[i];
	}
	cout<<ans<<endl;
}