#include<bits/stdc++.h>
using namespace std;
int n,k;
const int N = 1e6+10;
int a[N];
int main(){
    cin>>n>>k;
    unordered_map<int,int> ump,ump1;
    for(int i=1;i<=n;i++){
        int x;
        cin>>x;
        a[i]=x;
        ump[x]++;
        
    }
    int cf=a[0];
    int cnt=1;
    for(int i=2;i<=n;i++){
    	if(a[i]==a[i-1]){
    		cnt++;
		}else{
				ump1[cf+k]=max(ump1[cf+k],cnt);
				cf=a[i];
				cnt=1;
			}
	}
    int max1=0;
    for(auto x:ump){
        max1=max(max1,x.second+ump1[x.first]);
    }
//    cout<<ump[3]<<ump1[3]<<endl;
    cout<<max1;
}