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