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.File;import java.io.FileInputStream;import java.io.FileNotFoundException;
import java.io.IOException;import java.io.InputStream;import java.io.PrintStream;
import java.io.PrintWriter;import java.security.AccessControlException;import java.util.Arrays;
import java.util.Collection;import java.util.Comparator;import java.util.List;import java.util.Map;
import java.util.Objects;import java.util.TreeMap;import java.util.function.Function;
import java.util.stream.Collectors;import java.util.stream.IntStream;import java.util.stream.LongStream;
import java.util.stream.Stream;public class _p001119A {static public void main(final String[] args) 
throws IOException{p001119A._main(args);}
static private class p001119A extends Solver{public p001119A(){singleTest=true;}
@Override public void solve()throws IOException{int n=sc.nextInt();sc.nextLine();
int[]c=lineToIntArray();int res=0;if(c[0]!=c[n-1]){res=n-1;}else{int d1=0;int d2
=0;for(int i=1;i<n-1;i++){if(c[i]!=c[0]){if(d1==0){d1=n-1-i;}d2=i;}}res=Math.max(d1,
d2);}pw.println(res);}static public void _main(String[]args)throws IOException{new 
p001119A().run();}}static private class MyScanner{private StringBuilder cache=new 
StringBuilder();int cache_pos=0;private int first_linebreak=-1;private int second_linebreak
=-1;private StringBuilder sb=new StringBuilder();private InputStream is=null;public 
MyScanner(final InputStream is){this.is=is;}private String charToString(final int 
c){return String.format("'%s'",c=='\n'?"\\n":(c=='\r'?"\\r":String.valueOf((char)c)));
}public int get(){int res=-1;if(cache_pos<cache.length()){res=cache.charAt(cache_pos);
cache_pos++;if(cache_pos==cache.length()){cache.delete(0,cache_pos);cache_pos=0;
}}else{try{res=is.read();}catch(IOException ex){throw new RuntimeException(ex);}
}return res;}private void unget(final int c){if(cache_pos==0){cache.insert(0,(char)c);
}else{cache_pos--;}}public String nextLine(){sb.delete(0,sb.length());int c;boolean 
done=false;boolean end=false;while((c=get())!=-1){if(check_linebreak(c)){done=true;
if(c==first_linebreak){if(!end){end=true;}else{cache.append((char)c);break;}}else 
if(second_linebreak!=-1 && c==second_linebreak){break;}}if(end && c!=first_linebreak 
&& c!=second_linebreak){cache.append((char)c);break;}if(!done){sb.append((char)c);
}}return sb.toString();}private boolean check_linebreak(int c){if(c=='\n'|| c=='\r')
{if(first_linebreak==-1){first_linebreak=c;}else if(c!=first_linebreak && second_linebreak
==-1){second_linebreak=c;}return true;}return false;}public int nextInt(){return 
Integer.parseInt(next());}public long nextLong(){return Long.parseLong(next());}
public boolean hasNext(){boolean res=false;int c;while((c=get())!=-1){if(!check_linebreak(c)
&& c!=' '&& c!='\t'){res=true;unget(c);break;}}return res;}public String next(){
sb.delete(0,sb.length());boolean started=false;int c;while((c=get())!=-1){if(check_linebreak(c)
|| c==' '|| c=='\t'){if(started){unget(c);break;}}else{started=true;sb.append((char)c);
}}return sb.toString();}public int nextChar(){return get();}public boolean eof()
{int c=get();boolean res=false;if(c!=-1){unget(c);}else{res=true;}return res;}public 
double nextDouble(){return Double.parseDouble(next());}}static private class Pair<K,V>
{private K k;private V v;public Pair(final K t,final V u){this.k=t;this.v=u;}public 
K getKey(){return k;}public V getValue(){return v;}}static private abstract class 
Solver{protected String nameIn=null;protected String nameOut=null;protected boolean 
singleTest=false;protected boolean preprocessDebug=false;protected boolean doNotPreprocess
=false;protected PrintStream debugPrintStream=null;protected MyScanner sc=null;protected 
PrintWriter pw=null;final static String SPACE=" ";final static String SPACES="\\s+";
private int current_test=0;private int count_tests=0;protected int currentTest()
{return current_test;}protected int countTests(){return count_tests;}private void 
process()throws IOException{if(!singleTest){count_tests=lineToIntArray()[0];for(current_test
=1;current_test<=count_tests;current_test++){solve();pw.flush();}}else{count_tests
=1;current_test=1;solve();pw.flush();}}abstract protected void solve()throws IOException;
protected String[]lineToArray()throws IOException{return sc.nextLine().trim().split(SPACES);
}protected int[]lineToCharArray()throws IOException{return sc.nextLine().chars().toArray();
}protected int[]lineToIntArray()throws IOException{return Arrays.stream(lineToArray()).mapToInt(Integer::parseInt).toArray();
}protected long[]lineToLongArray()throws IOException{return Arrays.stream(lineToArray()).mapToLong(Long::parseLong).toArray();
}protected double[]lineToDoubleArray()throws IOException{return Arrays.stream(lineToArray()).mapToDouble(Double::parseDouble).toArray();
}protected void run()throws IOException{boolean done=false;try{if(nameIn!=null && 
new File(nameIn).exists()){try(FileInputStream fis=new FileInputStream(nameIn);PrintWriter 
pw0=select_output();){done=true;sc=new MyScanner(fis);pw=pw0;process();}}}catch(IOException 
ex){}catch(AccessControlException ex){}if(!done){try(PrintWriter pw0=select_output();
){sc=new MyScanner(System.in);pw=pw0;process();}}}private PrintWriter select_output()
throws FileNotFoundException{if(nameOut!=null){return new PrintWriter(nameOut);}
return new PrintWriter(System.out);}public static Map<Integer,Integer>mapc(final 
int[]a){return IntStream.range(0,a.length).collect(()->new TreeMap<Integer,Integer>(),
(res,i)->{res.put(a[i],res.getOrDefault(a[i],0)+1);},Map::putAll);}public static 
Map<Long,Integer>mapc(final long[]a){return IntStream.range(0,a.length).collect(
()->new TreeMap<Long,Integer>(),(res,i)->{res.put(a[i],res.getOrDefault(a[i],0)+
1);},Map::putAll);}public static<T>Map<T,Integer>mapc(final T[]a,Comparator<T>cmp)
{return IntStream.range(0,a.length).collect(cmp!=null?()->new TreeMap<T,Integer>(cmp)
:()->new TreeMap<T,Integer>(),(res,i)->{res.put(a[i],res.getOrDefault(a[i],0)+1);
},Map::putAll);}public static<T>Map<T,Integer>mapc(final T[]a){return mapc(a,null);
}public static Map<Integer,Integer>mapc(final IntStream a){return a.collect(()->
new TreeMap<Integer,Integer>(),(res,v)->{res.put(v,res.getOrDefault(v,0)+1);},Map::putAll
);}public static Map<Long,Integer>mapc(final LongStream a){return a.collect(()->
new TreeMap<Long,Integer>(),(res,v)->{res.put(v,res.getOrDefault(v,0)+1);},Map::putAll
);}public static<T>Map<T,Integer>mapc(final Stream<T>a,Comparator<T>cmp){return 
a.collect(cmp!=null?()->new TreeMap<T,Integer>(cmp):()->new TreeMap<T,Integer>(),
(res,v)->{res.put(v,res.getOrDefault(v,0)+1);},Map::putAll);}public static<T>Map<T,
Integer>mapc(final Stream<T>a){return mapc(a,null);}public static<T>Map<T,Integer>
mapc(final Collection<T>a,Comparator<T>cmp){return mapc(a.stream(),cmp);}public 
static<T>Map<T,Integer>mapc(final Collection<T>a){return mapc(a.stream());}public 
static Map<Integer,List<Integer>>mapi(final int[]a){return IntStream.range(0,a.length).collect(
()->new TreeMap<Integer,List<Integer>>(),(res,i)->{if(!res.containsKey(a[i])){res.put(a[i],
Stream.of(i).collect(Collectors.toList()));}else{res.get(a[i]).add(i);}},Map::putAll
);}public static Map<Long,List<Integer>>mapi(final long[]a){return IntStream.range(0,
a.length).collect(()->new TreeMap<Long,List<Integer>>(),(res,i)->{if(!res.containsKey(a[i]))
{res.put(a[i],Stream.of(i).collect(Collectors.toList()));}else{res.get(a[i]).add(i);
}},Map::putAll);}public static<T>Map<T,List<Integer>>mapi(final T[]a,Comparator<T>
cmp){return IntStream.range(0,a.length).collect(cmp!=null?()->new TreeMap<T,List<Integer>>(cmp)
:()->new TreeMap<T,List<Integer>>(),(res,i)->{if(!res.containsKey(a[i])){res.put(a[i],
Stream.of(i).collect(Collectors.toList()));}else{res.get(a[i]).add(i);}},Map::putAll
);}public static<T>Map<T,List<Integer>>mapi(final T[]a){return mapi(a,null);}public 
static Map<Integer,List<Integer>>mapi(final IntStream a){int[]i=new int[]{0};return 
a.collect(()->new TreeMap<Integer,List<Integer>>(),(res,v)->{if(!res.containsKey(v))
{res.put(v,Stream.of(i[0]).collect(Collectors.toList()));}else{res.get(v).add(i[0]);
}i[0]++;},Map::putAll);}public static Map<Long,List<Integer>>mapi(final LongStream 
a){int[]i=new int[]{0};return a.collect(()->new TreeMap<Long,List<Integer>>(),(res,
v)->{if(!res.containsKey(v)){res.put(v,Stream.of(i[0]).collect(Collectors.toList()));
}else{res.get(v).add(i[0]);}i[0]++;},Map::putAll);}public static<T>Map<T,List<Integer>>
mapi(final Stream<T>a,Comparator<T>cmp){int[]i=new int[]{0};return a.collect(cmp
!=null?()->new TreeMap<T,List<Integer>>(cmp):()->new TreeMap<T,List<Integer>>(),
(res,v)->{if(!res.containsKey(v)){res.put(v,Stream.of(i[0]).collect(Collectors.toList()));
}else{res.get(v).add(i[0]);}i[0]++;},Map::putAll);}public static<T>Map<T,List<Integer>>
mapi(final Stream<T>a){return mapi(a,null);}public static<T>Map<T,List<Integer>>
mapi(final Collection<T>a,Comparator<T>cmp){return mapi(a.stream(),cmp);}public 
static<T>Map<T,List<Integer>>mapi(final Collection<T>a){return mapi(a.stream());
}public static List<int[]>listi(final int[]a){return IntStream.range(0,a.length).mapToObj(i
->new int[]{a[i],i}).collect(Collectors.toList());}public static List<long[]>listi(final 
long[]a){return IntStream.range(0,a.length).mapToObj(i->new long[]{a[i],i}).collect(Collectors.toList());
}public static<T>List<Pair<T,Integer>>listi(final T[]a){return IntStream.range(0,
a.length).mapToObj(i->new Pair<T,Integer>(a[i],i)).collect(Collectors.toList());
}public static List<int[]>listi(final IntStream a){int[]i=new int[]{0};return a.mapToObj(v
->new int[]{v,i[0]++}).collect(Collectors.toList());}public static List<long[]>listi(final 
LongStream a){int[]i=new int[]{0};return a.mapToObj(v->new long[]{v,i[0]++}).collect(Collectors.toList());
}public static<T>List<Pair<T,Integer>>listi(final Stream<T>a){int[]i=new int[]{0};
return a.map(v->new Pair<T,Integer>(v,i[0]++)).collect(Collectors.toList());}public 
static<T>List<Pair<T,Integer>>listi(final Collection<T>a){int[]i=new int[]{0};return 
a.stream().map(v->new Pair<T,Integer>(v,i[0]++)).collect(Collectors.toList());}public 
static String join(final int[]a){return Arrays.stream(a).mapToObj(Integer::toString).collect(Collectors.joining(SPACE));
}public static String join(final long[]a){return Arrays.stream(a).mapToObj(Long::toString).collect(Collectors.joining(SPACE));
}public static<T>String join(final T[]a){return Arrays.stream(a).map(v->Objects.toString(v)).collect(Collectors.joining(SPACE));
}public static<T>String join(final T[]a,final Function<T,String>toString){return 
Arrays.stream(a).map(v->toString.apply(v)).collect(Collectors.joining(SPACE));}public 
static<T>String join(final Collection<T>a){return a.stream().map(v->Objects.toString(v)).collect(Collectors.joining(SPACE));
}public static<T>String join(final Collection<T>a,final Function<T,String>toString)
{return a.stream().map(v->toString.apply(v)).collect(Collectors.joining(SPACE));
}public static<T>String join(final Stream<T>a){return a.map(v->Objects.toString(v)).collect(Collectors.joining(SPACE));
}public static<T>String join(final Stream<T>a,final Function<T,String>toString){
return a.map(v->toString.apply(v)).collect(Collectors.joining(SPACE));}public static
<T>String join(final IntStream a){return a.mapToObj(Integer::toString).collect(Collectors.joining(SPACE));
}public static<T>String join(final LongStream a){return a.mapToObj(Long::toString).collect(Collectors.joining(SPACE));
}public static List<Integer>list(final int[]a){return Arrays.stream(a).mapToObj(Integer::valueOf).collect(Collectors.toList());
}public static List<Integer>list(final IntStream a){return a.mapToObj(Integer::valueOf).collect(Collectors.toList());
}public static List<Long>list(final long[]a){return Arrays.stream(a).mapToObj(Long::valueOf).collect(Collectors.toList());
}public static List<Long>list(final LongStream a){return a.mapToObj(Long::valueOf).collect(Collectors.toList());
}public static<T>List<T>list(final Stream<T>a){return a.collect(Collectors.toList());
}public static<T>List<T>list(final Collection<T>a){return a.stream().collect(Collectors.toList());
}public static<T>List<T>list(final T[]a){return Arrays.stream(a).collect(Collectors.toList());
}public static String yesNo(final boolean res){return res?"YES":"NO";}}}
