#include<iostream>
#include<algorithm>
using namespace std;
int main()
{
	int n;
	cin>>n;
	int A[n+1];
	for(int i=0;i<n;i++)
	{
		cin>>A[i];
	}
	int max=0;
	for(int j=0;j<n;j++)
	{
		int p,o=0,m=0,nn=0;
		for(int k=0;k<n;k++)
		{
			//cout<<"LOl";
			int r=A[j]-A[k];
			//cout<<r<<endl;
			if(r==0)
			m++;
			if(r==1)
			nn++;
			if(r==-1)
			o++;
		}
		//cout<<o<<" "<<m<<" "<<n<<" ";
		if(n>o)
		p=nn;
		else
		p=o;
		//cout<<p<<" ";
		if((p+m)>=max)
		max=p+m;
		//cout<<max<<" ";
	}
	cout<<max<<endl;
}