#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n,arr[105],count=0,count1=0,maxcount=0,maxcount1=0;
	cin>>n;
	for(int i=0;i<n;i++)
	{
		cin>>arr[i];
	}
	
	for(int i=0;i<n;i++)
	{   count=0;count1=0;
		for(int j=i+1;j<n;j++)
		{
			if(arr[i]-arr[j]==-1 || arr[i]-arr[j]==0)
			{
				count++;
				
			}
			 if(arr[i]-arr[j]==1 || arr[i]-arr[j]==0)
			{
				count1++;
			}
		}
		if(count>maxcount)
		maxcount=count;
		if(count1>maxcount1)
		maxcount1=count1;
	}
//	cout<<maxcount<<endl;
//	cout<<maxcount1<<endl;
	int m=max(maxcount,maxcount1);
//	cout<<m<<endl;
	int ans=m+1;
	cout<<ans<<endl;
}