n=int(input())
a=list(map(int,input().split()))
l=1
x,y=a[1]-a[0],0
for i in range(n-1):
 m=s[i+1]-s[i]
 if m!=x:
  l=max(l,i-y+1)
  x,y=m,i
print(max(l,n-y))