When Xellos was doing a practice course in university, he once had to measure the intensity of an effect that slowly approached equilibrium. A good way to determine the equilibrium intensity would be choosing a sufficiently large number of consecutive data points that seems as constant as possible and taking their average. Of course, with the usual sizes of data, it's nothing challenging- but why not make a similar programming contest problem while we're at it?

You're given a sequence of n data points a1,...,an. There aren't any big jumps between consecutive data points- for each 1 \le i \lt n, it's guaranteed that |ai+1-ai| \le 1.

A range [l,r] of data points is said to be almost constant if the difference between the largest and the smallest value in that range is at most 1. Formally, let M be the maximum and m the minimum value of ai for l \le i \le r; the range [l,r] is almost constant if M-m \le 1.

Find the length of the longest almost constant range.

The first line of the input contains a single integer n (2 \le n \le 100000)- the number of data points.

The second line contains n integers a1,a2,...,an (1 \le ai \le 100000).

Print a single number- the maximum length of an almost constant range of the given sequence.

In the first sample, the longest almost constant range is [2,5]; its length (the number of data points in it) is 4.

In the second sample, there are three almost constant ranges of length 4: [1,4], [6,9] and [7,10]; the only almost constant range of the maximum length 5 is [6,10].