#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<cstring>
#include<algorithm>

using namespace std;

const int oo=~0u>>1;

int N,M,ans,Num[100010];
long long K;

int main()
{
	freopen("balline.in","r",stdin);
	freopen("balline.out","w",stdout);
	scanf("%d%d",&N,&K);
	K=(1<<K);
	for(int i=1;i<=N;i++)
	{
		scanf("%d",&Num[i]);
		Num[i]%=K;
	}
	for(int i=1;i<N;i++)
	{
		long long tmp=Num[i];
		for(int j=i+1;j<=N;j++)
		{
			tmp^=Num[j];
			if(!tmp)
				ans=max(ans,j-i+1);
		}
	}
	if(N==1&&(Num[1]==K||!Num[1]))
		ans=1;
	printf("%d\n",ans);
	return 0;
}