#include<iostream>
using namespace std;long n,a[2010],i,d,s,h,j;int main(){cin>>n;for(i=0;i++<n;){cin>>a[i];}i=0;if(n==1)cout<<1;else{i=1;for(;j++<n;){h=a[j+1]-a[j];if(j==1)d=h;if(h!=d)i=1;s=max(s,i+++(j!=n));d=h;}cout<<s;}}