#include<bits/stdc++.h>

using namespace std;

typedef long long int ll;

int main(){
	ll n,j=0;
	cin>>n;
	ll a[n],b[n];
	ll max1=0,max2=0;
	for(int i=0;i<n;i++)
	cin>>a[i];
	for(int i=0;i<n;i++){
		ll count1=0,count2=0,max1=0;
		for(int j=0;j<n;j++){
			if(abs(a[i]-a[j])<=1 && a[i]<=a[j]){
				count1++;
				
			}
			if(abs(a[i]-a[j])<=1 && a[i]>=a[j]){
				count2++;
				
			}
			max1=max(count1,count2);
			if(max1>max2)
			max2=max1;
			
		}
	}
	cout<<max2;
	return 0;
	
}