#include <bits/stdc++.h>
using namespace std;
#define MAXN 500005
int a[MAXN];
struct node
{
node* nula;
node* kec;
int minpos=9999999;
//bool leaf;
};
node* root;
void update(int br,int pos)
{
node* now = root;
for(int i = 31; i >= 0; i--)
{
//if(now->minpos == NULL)now->minpos = 999999999;
now->minpos = min(now->minpos,pos);
if(br&(1<<i))
{
if(now->kec == NULL)now->kec = new node();
now = now->kec;
}
else
{
if(now->nula == NULL)now->nula = new node();
now = now->nula;
}
}
//if(now->minpos == NULL)now->minpos = 999999999;
now->minpos = min(now->minpos,pos);
}
int query(int br,int x)
{
//br je trazeni
//x je mojbroj
node* now = root;
int res = 9999999;
for(int i = 31; i >= 0; i--)
{
if(br & (1<<i))
{
if(x & (1<<i))
{
now = now->nula;
}
else
{
now = now->kec;
}
}
else
{
if(x & (1<<i))
{
res = min(res,now->nula->minpos);
now = now->kec;
}
else
{
res = min(res,now->kec->minpos);
now = now->nula;
}
}
}
res = min(res,now->minpos);
return res;
}
int main()
{
ios_base::sync_with_stdio(false);
int n,x;
cin >> n >> x;
root = new node();
update(0,1);
for(int i = 1; i <= n; i++)
{
cin >> a[i];
a[i]^=a[i-1];
}
int ans = 0;
for(int i = 1; i <= n; i++)
{
ans = max(ans,i-query(x,a[i])+1);
update(a[i],i);
}
cout << ans;
return 0;
}
