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.IOException;
import java.io.PrintWriter;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.NoSuchElementException;
import java.util.Objects;
import java.util.PriorityQueue;
import java.util.TreeSet;
public class Main{

	public static void main(String[] args){
		FastScanner sc = new FastScanner();
		PrintWriter out = new PrintWriter(System.out);
		Mathplus mp = new Mathplus();
		
		
		int n =sc.nextInt();
		int[] a = new int[n];
		for(int i=0;i<n;i++){
			a[i] = sc.nextInt();
		}
		if(a[0]!=a[n-1]){
			System.out.println(n-1);
			return;
		}else{
			int c = a[0];
			int max = 0;
			for(int i=1;i<n-1;i++){
				if(a[i]!=c){
					int mmax = Math.max(i,n-1-i);
					max = Math.max(max,mmax);
				}
			}
			System.out.println(max);
		}
	}

}


class UnionFindTree {
	int[] root;
	int[] rank;

	UnionFindTree(int N){
		root = new int[N];
		rank = new int[N];
		for(int i=0;i<N;i++){
			root[i] = i;
		}
	}

	public int find(int x){
		if(root[x]==x){
			return x;
		}else{
			return find(root[x]);
		}
	}

	public void unite(int x,int y){
		x = find(x);
		y = find(y);
		if(x==y){
			return;
		}else{
			if(rank[x]<rank[y]){
				root[x] = y;
			}else{
				root[y] = x;
				if(rank[x]==rank[y]){
					rank[x]++;
				}
			}
		}
	}

	public boolean same(int x,int y){
		return find(x)==find(y);
	}
}


class WeightedUnionFindTree extends UnionFindTree{
	int[] weight ;
	
	WeightedUnionFindTree(int N){
		super(N);
		weight = new int[N];
		for(int i=0;i<N;i++){
			weight[i] = 1;
		}
	}
	
	
	
	public void unite(int x,int y){
		x = find(x);
		y = find(y);
		if(x==y){
			return;
		}else{
			if(rank[x]<rank[y]){
				root[x] = y;
				weight[y] += weight[x];
			}else{
				root[y] = x;
				weight[x] += weight[y];
				if(rank[x]==rank[y]){
					rank[x]++;
				}
			}
		}
	}
	
}

class Graph {
	ArrayList<Edge>[] list;
	int size;
	TreeSet<LinkEdge> Edges = new TreeSet<LinkEdge>(new LinkEdgeComparator());
	@SuppressWarnings("unchecked")
	Graph(int N){
		size = N;
		list = new ArrayList[N];
		for(int i=0;i<N;i++){
			list[i] = new ArrayList<Edge>();
		}
	}

	void addEdge(int a,int b){
		list[a].add(new Edge(b,1));
	}

	void addWeightedEdge(int a,int b,int c){
		list[a].add(new Edge(b,c));
	}

	void addEgdes(int[] a,int[] b){
		int size = a.length;
		for(int i=0;i<size;i++){
			list[a[i]].add(new Edge(b[i],1));
		}
	}

	void addWeighterEdges(int[] a ,int[] b ,int[] c){
		int size = a.length;
		for(int i=0;i<size;i++){
			list[a[i]].add(new Edge(b[i],c[1]));
		}
	}

	long[] bfs(int s){
		long[] L = new long[size];
		for(int i=0;i<size;i++){
			L[i] = -1;
		}
		L[s] = 0;
		ArrayDeque<Integer> Q = new ArrayDeque<Integer>();
		Q.add(s);

		while(!Q.isEmpty()){
			int v = Q.poll();
			for(Edge e:list[v]){
				int w = e.to;
				long c = e.cost;
				if(L[w]==-1){
					L[w] = L[v] + c;
					Q.add(w);
				}
			}
		}

		return L;
	}

	long[] dijkstra(int s){
		long[] L = new long[size];
		for(int i=0;i<size;i++){
			L[i] = -1;
		}
		int[] visited = new int[size];
		L[s] = 0;
		PriorityQueue<Pair> Q = new PriorityQueue<Pair>(new SampleComparator());
		Q.add(new Pair(0,s));

		while(!Q.isEmpty()){

			Pair C = Q.poll();
			if(visited[(int)C.b]==0){
				L[(int)C.b] = C.a;
				visited[(int) C.b] = 1;
				for(Edge D:list[(int) C.b]){
					Q.add(new Pair(L[(int)C.b]+D.cost,D.to));
				}
			}
		}

		return L;
	}
	long Kruskal(){
		long ans = 0;

		UnionFindTree UF = new UnionFindTree(size);
		for(LinkEdge e:Edges){
			if(!UF.same(e.a,e.b)){
				ans += e.L;
				UF.unite(e.a,e.b);
			}
		}

		return ans;
	}
	
}


class LinkEdge{
	long L;
	int a ;
	int b;
	LinkEdge(long l,int A,int B){
		L = l;
		a = A;
		b = B;
	}
	public boolean equals(Object o){
		LinkEdge O = (LinkEdge) o;
		if(O.a==this.a&&O.b==this.b&&O.L==this.L){
			return true;
		}else{
			return false;
		}


	}

	public int hashCode(){
		return Objects.hash(L,a,b);
	}

}

class Edge{
	int to;
	long cost;

	Edge(int a,long b){
		to = a;
		cost = b;
	}

}
class LinkEdgeComparator implements Comparator<LinkEdge>{
	public int compare(LinkEdge P, LinkEdge Q) {
		long temp = P.L-Q.L;
		if(temp==0){
			if(P.a>Q.a){
				return 1;
			}else{
				if(P.b>Q.b){
					return 1;
				}else{
					return -1;
				}
			}

		}
		if(temp>=0){
			return 1;
		}else{
			return -1;
		}
	}

}
class Pair{
	long a;
	long b;

	Pair(long p,long q){
		this.a = p;
		this.b = q;
	}

	public boolean equals(Object o){
		Pair O = (Pair) o;
		if(O.a==this.a&&O.b==this.b){
			return true;
		}else{
			return false;
		}


	}

	public int hashCode(){
		return Objects.hash(a,b);
	}

}

class SampleComparator implements Comparator<Pair>{
	public int compare(Pair P, Pair Q) {
		long temp = P.a-Q.a;
		if(temp==0){
			if(P.b>Q.b){
				return 1;
			}else{
				return -1;
			}

		}
		if(temp>=0){
			return 1;
		}else{
			return -1;
		}
	}

}

class FastScanner {
    private final java.io.InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    }
    private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
    private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
    private void skipUnprintable() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;}
    public boolean hasNext() { skipUnprintable(); return hasNextByte();}
    public String next() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }
    public long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while(true){
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return (minus ? -n : n);
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
    public int nextInt() {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while(true){
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return (int) (minus ? -n : n);
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
}

class Mathplus{
	int mod = 1000000007;
	long[] fac = new long[1000001];
	boolean isBuild = false;
	int mindex = -1;
	int maxdex = -1;


	void buildFac(){
		fac[0] = 1;
		for(int i=1;i<=1000000;i++){
			fac[i] = (fac[i-1] * i)%mod;
		}
		isBuild = true;
	}
	long max(long[] a){
		long max = 0;
		for(int i=0;i<a.length;i++){
			if(max<a[i]){
				max =a[i];
				maxdex = i;
			}
		}
		return max;
	}
	int max(int[] a){
		int max = 0;
		for(int i=0;i<a.length;i++){
			if(max<a[i]){
				max =a[i];
				maxdex = i;
			}
		}
		return max;
	}
	long min(long[] a){
		long min = Long.MAX_VALUE;
		for(int i=0;i<a.length;i++){
			if(min>a[i]){
				min =a[i];
				mindex = i;
			}
		}
		return min;
	}
	int min(int[] a){
		int min = Integer.MAX_VALUE;
		for(int i=0;i<a.length;i++){
			if(min>a[i]){
				min =a[i];
				mindex = i;
			}
		}
		return min;
	}
	long sum(long[] a){
		long sum = 0;
		for(int i=0;i<a.length;i++){
			sum += a[i];
		}
		return sum;
	}
	long sum(int[] a){
		long sum = 0;
		for(int i=0;i<a.length;i++){
			sum += a[i];
		}
		return sum;
	}

	long gcd(long a, long b){
		if(a<b){
			a^=b;
			b^=a;
			a^=b;
		}
		if(a%b==0){
			return b;
		}else{
			return gcd(b,a%b);
		}
	}

	long lcm(long a, long b){
		return a / gcd(a,b) * b;
	}

	public long comb(int a,int num){
		if(!isBuild){
			buildFac();
		}
		return fac[a] * (rev(fac[num])*rev(fac[a-num])%mod)%mod;
	}

	long rev(long l) {
		return pow(l,mod-2);
	}

	long pow(long l, int i) {
		if(i==0){
			return 1;
		}else{
			if(i%2==0){
				long val = pow(l,i/2);
				return val * val % mod;
			}else{
				return pow(l,i-1) * l % mod;
			}
		}
	}


}
