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. 
import java.io.*;
import java.util.*;
import java.util.Queue;
import java.util.LinkedList;
import java.util.Stack;
import java.math.*;
public class Solution
{
    @SuppressWarnings("unchecked")
    static long s[],a[],k=0,sum=0;
    static Vector adj[];static int x=0;
     public static void main(String args[])throws IOException
    {
        Reader ob=new Reader();
        Writer out=new Writer(System.out);
        int n=ob.nI();
        int a[]=ob.NIA(n);
        int dis=0;
        for(int i=0;i<n;i++)
            if(a[i]!=a[n-1])
            {
            dis=max(dis,n-1-i);
            break;
        }
        for(int i=n-1;i>=0;i--)
            if(a[i]!=a[0])
            {
            dis=max(dis,i);
            break;
        }
        out.pln(dis);
            
    out.flush();
}
static void dfsum(int n)
{
    int l=adj[n].size();
    long su=a[n];
    for(int i=0;i<l;i++)
    {
        
        int r=(int)adj[n].get(i);
        dfsum(r);
        su+=s[r];
    }
    s[n]=su;
    
}
static void dfs(int n)
{
    int l=adj[n].size();
    if(!(s[n]<0&&s[n]+x<0&&a[n]<0))
    {
    for(int i=0;i<l;i++)
    {
        int r=(int)adj[n].get(i);
        dfs(r);
    }
}
    else
{
    sum=sum-s[n]-x;
    
}
}
static void bfs(int ss)
{
    
        Queue q=new Queue();
        q.add(ss);
        while(!q.isEmpty())
        {
            int r=q.remove();
            if(s[r]>0)
            {
            int l=adj[r].size();
            for(int i=0;i<l;i++)
            {
                int y=(int)adj[r].get(i);
                
            }
        }
        else
        {
            k++;
            sum-=s[r];
        }
    }
        
        
        
    
    
}
public static void bfs(int s, ArrayList<Integer> adj[],boolean vis[],int n)
    {
        //Add your code here.
        Queue q=new Queue();
        q.add(s);
        vis[s]=true;
        while(!q.isEmpty())
        {
            int r=q.remove();
            int l=adj[r].size();
            for(int i=0;i<l;i++)
            {
                int y=adj[r].get(i);
                if(!vis[y])
                {
                    q.add(y);
                    vis[y]=true;

                }
               
            }
        }
    }
static void debug(Object... o) {
        System.err.println(Arrays.deepToString(o));
    }
static long inverse(long x, long p)
    {
        return pow(x, p - 2, p);
    }
static boolean isPrime(long n)
{
    long h=(long)Math.sqrt(n);
    for(long i=2;i<=h;i++)
    if(n%i==0)
    return false;
    return true&&n!=1;
}
    static long gcd(long a,long b)
    {
        if(a<b)
        return gcd(b,a);
        else if(b==0)
        return a;
        else
        return gcd(b,a%b);
    }
    static long pow(long a,long b,long mod){
		if(b == 0)	return 1;
		long t = pow(a,b>>1,mod);
		t = (t * t) % mod;
		if((b & 1) == 1)	t = (t * a);
		if(t >= mod)	t %= mod;
		return t;
}
    static long pow(long a,long b){
		if(b == 0)	return 1;
		long t = pow(a,b>>1);
		t = (t * t);
		if((b & 1) == 1)	t = (t * a);
		return t;
}
    static void seive(int n,int prime[])//1 for prime -1 for not prime
    {
        for(int i=2;i<=n;i++)
            if(prime[i]==0)
            {
                prime[i]=1;
                for(int j=2;j*i<=n;j++)
                prime[j*i]=-1;
            }
    }
    static int max(int ...a)
    {
        int m=a[0];
        for(int i=0;i<a.length;i++)
        m=Math.max(m,a[i]);
        return m;
        
    }
    static long max(long ...a)
    {
        long m=a[0];
        for(int i=0;i<a.length;i++)
        m=Math.max(m,a[i]);
        return m;
    }
    static int min(int ...a)
    {
        int m=a[0];
        for(int i=0;i<a.length;i++)
        m=Math.min(m,a[i]);
        return m;
    }
    static long min(long ...a)
    {
        long m=a[0];
        for(int i=0;i<a.length;i++)
        m=Math.min(m,a[i]);
        return m;
    }
    static class Pair
    {
        int x=0,y=0;
        Pair(int xx,int yy)
        {
            x=xx;
            y=yy;
        }
    }
    static class Queue
{
    Node head,tail;
    void add(int n)
    {
       Node tmp=new Node(n);
       if(head==null)
       {
           head=tmp;
           tail=tmp;
        }
        else
        {
            tail.next=tmp;
            tail=tmp;
        }
    }
    int remove()
   {
       if(head!=null)
       {
           int d=head.data;
           head=head.next;
           return d;
        }
        return -1;
    }
    int peek()
    {
        if(head!=null)
        return head.data;
        return -1;
    }
    void display()
    {
        Node tmp=head;
        while(tmp!=null)
        {
            System.out.print(tmp.data+" ");
            tmp=tmp.next;
        }
        System.out.println();
    }
    boolean isEmpty()
    {
        return head==null;
    }
}
static class Node 
{
    int data;
    Node next;
    Node(int n)
    {
       data=n;
    }
}
	static class Writer {
		private final PrintWriter p;
		Writer(OutputStream o) {
			p = new PrintWriter(new BufferedWriter(new OutputStreamWriter(o)));
		}
		void p(Object... o1) {
			for (Object o11 : o1) {
				p.print(o11 + "" );
			}
		}
		void p(String s) {
			p.print(s);
		}
		void pln(Object... o1) {
			p(o1);
			p.println();
		}
		void flush() {
			p.flush();
		}
		void close() {
			p.close();
		}
	}
    static class Reader {
		private byte[] buf = new byte[1024];
		private int curChar;
		private int snumChars;
		public int read() {
			if (snumChars == -1)
				throw new InputMismatchException();
			if (curChar >= snumChars) {
				curChar = 0;
				try {
					snumChars = System.in.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (snumChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}
		public String nl() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndOfLine(c));
			return res.toString();
		}
		public String n() {
			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 long nL() {
			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 int nI() {
			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 int[] NIA(int n) //nextINtArray
		{
			int[] arr = new int[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nI();
			}
			return arr;
		}
		public int[] NIA1(int n) //nextINtArray
		{
			int[] arr = new int[n+1];
			for (int i = 1; i <=n; i++) {
				arr[i] = nI();
			}
			return arr;
		}
		
		public long[] NLA(int n) //nextLongArray
		{
			long[] arr = new long[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nL();
			}
			return arr;
}
		public long[] NLA1(int n) //nextLongArray
		{
			long[] arr = new long[n+1];
			for (int i = 1; i <=n; i++) {
				arr[i] = nL();
			}
			return arr;
}
		private boolean isSpaceChar(int c) {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}
		private boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}
	}
static class DisJoint
{
    int a[],rank[];
    DisJoint(int n)
    {
        a=new int[n+1];
        rank=new int[n+1];
        for(int i=1;i<=n;i++)
    {
        a[i]=i;
        rank[i]=1;
    }
    }
    int find(int n)
    {
        if(a[n]==n)
        return n;
        else
        return find(a[n]);
    }
    void union(int a1,int b)
    {
        int x=find(a1);
        int y=find(b);
        if(rank[x]>rank[y])
    {
        a[y]=x;
        rank[x]+=1;
    }
    else
    {
       a[x]=y;
       rank[y]+=1;
    }
        //System.out.println(Arrays.toString(a));
    }
}
class Segment
{
    int sum[];
    void build(int a[],int v,int l,int r)
    {
        if(l==r)
        sum[v]=a[l];
        else
        {
            int m=(l+r)/2;
            build(a,v*2,l,m);
            build(a,2*v+1,m+1,r);
            sum[v]=sum[v*2]+sum[2*v+1];
        }
    }
    void update(int a[],int l,int r,int x,int v,int y)
    {
        if(l==r&&r==y)
            sum[v]+=x;
        else if(l>y||y>r)
        return;
        else
        {
            int m=(l+r)/2;
            update(a,l,m,x,2*v,y);
            update(a,m+1,r,x,2*v+1,y);
            sum[v]=sum[2*v]+sum[2*v+1];
        }
    }
    int query(int v,int l,int r,int x,int y)
    {
        if(x>r||y<l)
        return 0;
        else if(x<=l&&r<=y)
        return sum[v];
        else
        {
            int m=(l+r)/2;
        return query(2*v,l,m,x,y)+query(2*v+1,m+1,r,x,y);  
    }
}
}

static class Trie
  {
      Trie child[]=new Trie[26];
      int count=0;
    }
   /* void insert(String a)
    {
        Trie tmp=root;
        for(int i=0;i<a.length();i++)
        {
            int v=a.charAt(i)-'a';
            if(tmp.child[v]==null)
            {
                tmp.child[v]=new Trie();
                
            }
                tmp=tmp.child[v];
            }
            if(tmp.count==0)
            r++;
            tmp.count=1;
        }*/
    }