In the town of Pirates, Captain Jack is the best pirate. Captain Smith is jealous of Jack's popularity. So he challenged Jack to solve the following puzzle:
Given an array A, find the length of the largest contiguous sub-array such that the difference between any two consecutive elements in the sub-array is 1. Captain Jack is a little confused, so he called you, a programmer, for solving this puzzle.

INPUT

First line of input contains a number N i.e. the number of elements in array A. The next line contains N space separated integers representing elements of array.

OUTPUT

Print the largest length of contiguous sub-array satisfying the above given property.

CONSTRAINTS

1 ≤ N ≤ 100000     
0 ≤ A[ i ] ≤ 100000 

SAMPLE INPUT
6
1 3 5 7 8 9

SAMPLE OUTPUT
3
import math
n=input()
x=map(int,raw_input().split())
m=0
for i in xrange(1,n):
	c=1
	while i<n and math.fabs(x[i]-x[i-1])==1:
		#print i,x[i-1],x[i]
		c+=1
		i+=1
	
	if m<c:
		m=c
	
print m