#include<cstdio>
#include<algorithm>
#include<vector>
#include<map>
#define mkp make_pair
using namespace std;
map<vector<int>,int> a;
int n,m,ans,mp[114514];
pair<vector<int >,int> to(int a){
	int tel[1140]={0},tot=0;
	while(a){
		tel[++tot]=a-2*(a>>1);
		a>>=1;
	}
	vector<int > v;
	for(int i=1;i<=tot;i++){
		if(tel[i])mp[i]++;
		v.push_back(mp[i]);
	}
	for(int i=2;i<=m;i++)if(mp[i-1]!=mp[i])return mkp(v,0);
	return mkp(v,1);
}
signed main(){
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;i++){
		int x=0;
		scanf("%d",&x);
		pair<vector<int >,int> ps=to(x);
		vector<int> v=ps.first;
		int sb=ps.second;
		if(sb)ans=max(ans,i-a[v]+1);
		else a[v]=i;
	}
	printf("%d",ans);
	return 0;
}