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
n = input()
max = 1
c = 1
l = map(int,raw_input().strip().split())
for i in range(1,n):
  if abs(l[i] - l[i-1]) == 1:
    c+=1
    if c > max:
      max = c
  else:
    c = 0
print max+1