Ilya lives in a beautiful city of Chordalsk.

There are n houses on the street Ilya lives, they are numerated from 1 to n from left to right; the distance between every two neighboring houses is equal to 1 unit. The neighboring houses are 1 and 2, 2 and 3, ..., n-1 and n. The houses n and 1 are not neighboring.

The houses are colored in colors c_1, c_2, …, c_n so that the i-th house is colored in the color c_i. Everyone knows that Chordalsk is not boring, so there are at least two houses colored in different colors.

Ilya wants to select two houses i and j so that 1 ≤ i < j ≤ n, and they have different colors: c_i ≠ c_j. He will then walk from the house i to the house j the distance of (j-i) units.

Ilya loves long walks, so he wants to choose the houses so that the distance between them is the maximum possible.

Help Ilya, find this maximum possible distance.

Input

The first line contains a single integer n (3 ≤ n ≤ 300 000) — the number of cities on the street.

The second line contains n integers c_1, c_2, …, c_n (1 ≤ c_i ≤ n) — the colors of the houses.

It is guaranteed that there is at least one pair of indices i and j so that 1 ≤ i < j ≤ n and c_i ≠ c_j.

Output

Print a single integer — the maximum possible distance Ilya can walk.

Examples

Input


5
1 2 3 2 3


Output


4


Input


3
1 2 1


Output


1


Input


7
1 1 3 1 1 1 1


Output


4

Note

In the first example the optimal way is to walk from the first house to the last one, where Ilya can walk the distance of 5-1 = 4 units.

In the second example the optimal way is to either walk from the first house to the second or from the second to the third. Both these ways have the distance of 1 unit.

In the third example the optimal way is to walk from the third house to the last one, where Ilya can walk the distance of 7-3 = 4 units. 
//package codeforces.contests;

import java.io.*;
import java.util.InputMismatchException;
import java.util.Random;

/**
 * @author tainic on Apr 6, 2019
 */
public class AA {

    private static boolean LOCAL;
    static {
        try { LOCAL = "aurel".equalsIgnoreCase(System.getenv().get("USER")); } catch (Exception e){}
    }

    private static final String TEST =
        "3\n" +
        "1 3 1";

    void solve(InputReader in, PrintWriter out) {
        int n = in.nextInt();
        int[] a = Util.readInts(in, n);
        if (a[0] != a[n - 1]) {
            out.println(n - 1);
        } else {
            int i = 0;
            while (a[i] == a[0]) {
                i++;
            }
            int j = n - 1;
            while (a[j] == a[0]) {
                j--;
            }
            out.println(Math.max(n - 1 - i, j));
        }
    }

    //region util
    static class Util {

        private static final Random R = new Random();

        public static void sort(int[] a) {
            sort(a, 0, a.length - 1);
        }

        private static void sort(int[] a, int from, int to) {
            if (from >= to) {
                return;
            }

            // partition
            int pivotIndex = R.nextInt(to - from + 1) + from;
            int pivot = a[pivotIndex];
            // maintain this invariant, at each step i:
            // a[j] <  pivot, for j = fromIndex to lt - 1
            // a[j] == pivot, for j = lt to i - 1
            // a[j] >  pivot, for j = gt + 1 to toIndex
            int lt = from;
            int gt = to;
            int i = lt;
            while (i <= gt) {
                int cmp = a[i] - pivot;
                if (cmp < 0) {
                    swap(a, i, lt);
                    i++;
                    lt++;
                } else if (cmp > 0) {
                    swap(a, i, gt);
                    gt--;
                } else {
                    i++;
                }
            }

            // sort left and right
            sort(a, from, lt - 1);
            sort(a, gt + 1, to);
        }

        public static int findFirst(int[] a, int key) {
            return findFirstOrLast(a, key, 0, a.length - 1, -1);
        }

        public static int findLast(int[] a, int key) {
            return findFirstOrLast(a, key, 0, a.length - 1, 1);
        }

        public static int findFirstOrLast(int[] a, int key, int fromIndex, int toIndex, int dir) {
            int left = fromIndex;
            int right = toIndex;
            while (left <= right) {
                int mid = (left + right) >>> 1;
                int cmp = key - a[mid];
                if (cmp > 0) {
                    left = mid + 1;
                } else if (cmp < 0) {
                    right = mid - 1;
                } else if (dir == -1 && mid > fromIndex && a[mid - 1] == key) {
                    right = mid - 1;
                } else if (dir == 1 && mid < toIndex && a[mid + 1] == key) {
                    left = mid + 1;
                } else {
                    return mid;
                }
            }
            return -left - 1;
        }

        public static void swap(int[] a, int i, int j) {
            if (i != j) {
                int ai = a[i];
                a[i] = a[j];
                a[j] = ai;
            }
        }

        public static int[] readInts(InputReader in, int k) {
            int[] a = new int[k];
            for (int i = 0; i < k; i++) {
                a[i] = in.nextInt();
            }
            return a;
        }

    }
    //endregion

    //region main
    public static void main(String[] args) throws Exception {
        long t = System.currentTimeMillis();

        try (
            InputReader in = new StreamInputReader(!LOCAL ? System.in : new ByteArrayInputStream(TEST.getBytes()));
            PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out, 2048), false)
        ) {
            new AA().solve(in, out);
        }

        System.err.println("time: " + (System.currentTimeMillis() - t) + "ms");
    }
    //endregion

    //region fast io
    abstract static class InputReader implements AutoCloseable {

        public abstract int read();

        public int nextInt() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public long nextLong() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public String next() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }
    }

    static class StreamInputReader extends InputReader {

        private InputStream stream;
        private byte[] buf;
        private int curChar, numChars;

        public StreamInputReader(InputStream stream) {
            this(stream, 2048);
        }

        public StreamInputReader(InputStream stream, int bufSize) {
            this.stream = stream;
            this.buf = new byte[bufSize];
        }

        @Override
        public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }

        @Override
        public void close() throws Exception {
            stream.close();
        }

    }
    //endregion

    //region imports
    //endregion

}