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 ≤ i < n, it's guaranteed that |ai + 1 - ai| ≤ 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 ≤ i ≤ r; the range [l, r] is almost constant if M - m ≤ 1.

Find the length of the longest almost constant range.

Input

The first line of the input contains a single integer n (2 ≤ n ≤ 100 000) — the number of data points.

The second line contains n integers a1, a2, ..., an (1 ≤ ai ≤ 100 000).

Output

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

Examples

Input

5
1 2 3 3 2


Output

4


Input

11
5 4 5 5 6 7 8 8 8 7 6


Output

5

Note

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].
import java.util.Scanner;

public class ApproximatingAConstantRange {
  
  public static int UNDEFINED = 2;
 
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    
    int n = sc.nextInt();
    int a[] = new int[n];
    for (int i = 0; i < n; i++) {
      a[i] = sc.nextInt();
    }
    
    int maxlen = 0;
    int lastdiff = UNDEFINED, lastdiffIdx = -1;
    int l = 0, r;
    for (r = 0; r < n-1; r++) {
      int diff = a[r+1] - a[r];
      // System.out.println(a[r+1] + "-" + a[r] + "=" + diff);
      if (diff != 0) {
        if (lastdiff == UNDEFINED) {
          lastdiff = diff;
          lastdiffIdx = r+1; // resume at lastdiffIdx when consecutive +1 or -1 happens
        }
        else {
          if (lastdiff == diff) { // consecutive +1 or -1
            int len = r-l+1;
            // System.out.printf("l: %d, r: %d\n", l, r);
            if (len > maxlen) {
              maxlen = len;
              // System.out.printf("max: l: %d, r: %d\n", l, r);
            }
            lastdiff = UNDEFINED;
            l = lastdiffIdx;
            r = lastdiffIdx-1; // because after this, r will be incremented before the next iteration
          }
          else {
            lastdiff = diff;
            lastdiffIdx = r+1;
          }
        }
      }
    }
    
    int len = r-l+1; // last almost stable stretch
    if (len > maxlen) {
      maxlen = len;
//      System.out.printf("l: %d, r: %d\n", l, r);
    }
    
    System.out.println(maxlen);
  }

}