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.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Atharva Nagarkar
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        BApproximatingAConstantRange solver = new BApproximatingAConstantRange();
        solver.solve(1, in, out);
        out.close();
    }

    static class BApproximatingAConstantRange {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt();
            int[] a = new int[n];
            for (int i = 0; i < n; ++i) a[i] = in.nextInt();
            BApproximatingAConstantRange.RMQ rmq = new BApproximatingAConstantRange.RMQ(a);
            int low = 1;
            int high = n;
            while (low <= high) {
                int mid = low + high >> 1;
                boolean found = false;
                for (int l = 0, r = mid - 1; r < n; ++l, ++r) {
                    int min = rmq.minquery(l, r);
                    int max = rmq.maxquery(l, r);
                    if (max - min <= 1) {
                        found = true;
                        break;
                    }
                }
                if (!found) {
                    high = mid - 1;
                } else {
                    low = mid + 1;
                }
            }
            out.println(high);
        }

        static class RMQ {
            int[] vs;
            int[][] minlift;
            int[][] maxlift;

            public RMQ(int[] vs) {
                this.vs = vs;
                int n = vs.length;
                int maxlog = Integer.numberOfTrailingZeros(Integer.highestOneBit(n)) + 2;
                minlift = new int[maxlog][n];
                maxlift = new int[maxlog][n];
                for (int i = 0; i < n; i++)
                    minlift[0][i] = maxlift[0][i] = vs[i];
                int lastRange = 1;
                for (int lg = 1; lg < maxlog; lg++) {
                    for (int i = 0; i < n; i++) {
                        minlift[lg][i] = Math.min(minlift[lg - 1][i], minlift[lg - 1][Math.min(i + lastRange, n - 1)]);
                        maxlift[lg][i] = Math.max(maxlift[lg - 1][i], maxlift[lg - 1][Math.min(i + lastRange, n - 1)]);
                    }
                    lastRange *= 2;
                }
            }

            public int maxquery(int low, int hi) {
                int range = hi - low + 1;
                int exp = Integer.highestOneBit(range);
                int lg = Integer.numberOfTrailingZeros(exp);
                return Math.max(maxlift[lg][low], maxlift[lg][hi - exp + 1]);
            }

            public int minquery(int low, int hi) {
                int range = hi - low + 1;
                int exp = Integer.highestOneBit(range);
                int lg = Integer.numberOfTrailingZeros(exp);
                return Math.min(minlift[lg][low], minlift[lg][hi - exp + 1]);
            }

        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

    }
}

