n=int(input())
a=list(map(int,input().split()))
r=a[1]-a[0] if len(a)>1 else None
m,c=1,1
for i in range(0,n-1):
 if r==a[i+1]-a[i]: c+=1
 else: m,c,r=max(m,c),2,a[i+1]-a[i];
print(max(m,c))