Problem: Little Robber Girl likes to scare animals in her zoo for fun. She decided to arrange the animals in a row in the order of non-decreasing height. However, the animals were so scared that they couldn't stay in the right places.

The robber girl was angry at first, but then she decided to arrange the animals herself. She repeatedly names numbers l and r such that r - l + 1 is even. After that animals that occupy positions between l and r inclusively are rearranged as follows: the animal at position l swaps places with the animal at position l + 1, the animal l + 2 swaps with the animal l + 3, ..., finally, the animal at position r - 1 swaps with the animal r.

Help the robber girl to arrange the animals in the order of non-decreasing height. You should name at most 20 000 segments, since otherwise the robber girl will become bored and will start scaring the animals again.

Input

The first line contains a single integer n (1 ≤ n ≤ 100) — number of animals in the robber girl's zoo.

The second line contains n space-separated integers a1, a2, ..., an (1 ≤ ai ≤ 109), where ai is the height of the animal occupying the i-th place.

Output

Print the sequence of operations that will rearrange the animals by non-decreasing height.

The output should contain several lines, i-th of the lines should contain two space-separated integers li and ri (1 ≤ li < ri ≤ n) — descriptions of segments the robber girl should name. The segments should be described in the order the operations are performed.

The number of operations should not exceed 20 000.

If the animals are arranged correctly from the start, you are allowed to output nothing.

Examples

Input

4
2 1 4 3


Output

1 4


Input

7
36 28 57 39 66 69 68


Output

1 4
6 7


Input

5
1 2 1 2 1


Output

2 5
3 4
1 4
1 4

Note

Note that you don't have to minimize the number of operations. Any solution that performs at most 20 000 operations is allowed.

Solution (in JAVA):

Solution:
import java.util.ArrayList;
import java.util.InputMismatchException;
import java.util.Locale;
import java.util.Scanner;
import java.util.regex.Pattern;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.math.BigInteger;

public class LittleRobberGirlsZoo {

	public static void main(String[] args) {

		int n = StdIn.readInt();
		int[] a = new int[n+1];
		int min = Integer.MAX_VALUE;
		for(int i = 1 ; i <= n ; i++){
			a[i] = StdIn.readInt();
			min = Math.min(min, a[i]);
		}
		
		while(!isSorted(a)){
			for(int i = 1 ; i < n ; i++){
				int j = i + 1;	
				if(a[j] >= a[i])
					continue;
				if(i%2 == 1){
					if(n%2==1){
						swap(a, i, n-1);
						StdOut.println(i + " " + (n-1));
					}else{
						swap(a, i, n);
						StdOut.println(i + " " + (n));
					}
				}else{
					if(n%2==1){
						swap(a, i, n);
						StdOut.println(i + " " + (n));
					}else{
						swap(a, i, n-1);
						StdOut.println(i + " " + (n-1));
						}
				}
			}
		}
		
	}
	
	public static boolean isSorted(int[] a){
		for(int i = 1 ; i < a.length ; i++)
			if(a[i] < a[i-1])
				return false;
		return true;
	}
	
	public static void swap(int[] a, int i, int j){
		for(int index = i ; index <= j; index += 2){
			int t = a[index];
			a[index] = a[index+1];
			a[index+1] = t;
		}
		return;
	}

}

final class StdIn {
 
    private StdIn() { }
 
    private static Scanner scanner;
    
    private static final String CHARSET_NAME = "UTF-8";
 
    private static final Locale LOCALE = Locale.US;
 
    private static final Pattern WHITESPACE_PATTERN = Pattern.compile("\\p{javaWhitespace}+");
 
    private static final Pattern EMPTY_PATTERN = Pattern.compile("");
 
    private static final Pattern EVERYTHING_PATTERN = Pattern.compile("\\A");
 
    public static boolean isEmpty() {
        return !scanner.hasNext();
    }
 
    public static boolean hasNextLine() {
        return scanner.hasNextLine();
    }
 
    public static boolean hasNextChar() {
        scanner.useDelimiter(EMPTY_PATTERN);
        boolean result = scanner.hasNext();
        scanner.useDelimiter(WHITESPACE_PATTERN);
        return result;
    }
 
    public static String readLine() {
        String line;
        try                 { line = scanner.nextLine(); }
        catch (Exception e) { line = null;               }
        return line;
    }
 
    public static char readChar() {
        scanner.useDelimiter(EMPTY_PATTERN);
        String ch = scanner.next();
        assert (ch.length() == 1) : "Internal (Std)In.readChar() error!"
            + " Please contact the authors.";
        scanner.useDelimiter(WHITESPACE_PATTERN);
        return ch.charAt(0);
    }  
 
 
    public static String readAll() {
        if (!scanner.hasNextLine())
            return "";
 
        String result = scanner.useDelimiter(EVERYTHING_PATTERN).next();
        // not that important to reset delimeter, since now scanner is empty
        scanner.useDelimiter(WHITESPACE_PATTERN); // but let's do it anyway
        return result;
    }
 
    public static String readString() {
        return scanner.next();
    }
 
    public static int readInt() {
        return scanner.nextInt();
    }
 
    public static double readDouble() {
        return scanner.nextDouble();
    }
 
    public static float readFloat() {
        return scanner.nextFloat();
    }
 
    public static long readLong() {
        return scanner.nextLong();
    }
    
    public static short readShort() {
        return scanner.nextShort();
    }
 
    public static byte readByte() {
        return scanner.nextByte();
    }
 
    public static boolean readBoolean() {
        String s = readString();
        if (s.equalsIgnoreCase("true"))  return true;
        if (s.equalsIgnoreCase("false")) return false;
        if (s.equals("1"))               return true;
        if (s.equals("0"))               return false;
        throw new InputMismatchException();
    }
 
    public static String[] readAllStrings() {
        // we could use readAll.trim().split(), but that's not consistent
        // because trim() uses characters 0x00..0x20 as whitespace
        String[] tokens = WHITESPACE_PATTERN.split(readAll());
        if (tokens.length == 0 || tokens[0].length() > 0)
            return tokens;
 
        // don't include first token if it is leading whitespace
        String[] decapitokens = new String[tokens.length-1];
        for (int i = 0; i < tokens.length - 1; i++)
            decapitokens[i] = tokens[i+1];
        return decapitokens;
    }
 
    public static String[] readAllLines() {
        ArrayList<String> lines = new ArrayList<String>();
        while (hasNextLine()) {
            lines.add(readLine());
        }
        return lines.toArray(new String[0]);
    }
 
    public static int[] readAllInts() {
        String[] fields = readAllStrings();
        int[] vals = new int[fields.length];
        for (int i = 0; i < fields.length; i++)
            vals[i] = Integer.parseInt(fields[i]);
        return vals;
    }
 
    public static double[] readAllDoubles() {
        String[] fields = readAllStrings();
        double[] vals = new double[fields.length];
        for (int i = 0; i < fields.length; i++)
            vals[i] = Double.parseDouble(fields[i]);
        return vals;
    }
    
    static {
        resync();
    }
 
    private static void resync() {
        setScanner(new Scanner(new java.io.BufferedInputStream(System.in), CHARSET_NAME));
    }
    
    private static void setScanner(Scanner scanner) {
        StdIn.scanner = scanner;
        StdIn.scanner.useLocale(LOCALE);
    }
 
    public static int[] readInts() {
        return readAllInts();
    }
 
    public static double[] readDoubles() {
        return readAllDoubles();
    }
 
    public static String[] readStrings() {
        return readAllStrings();
    }
 
}
 
final class StdOut {
 
    private static final String CHARSET_NAME = "UTF-8";
 
    private static final Locale LOCALE = Locale.US;
 
    private static PrintWriter out;
 
    static {
        try {
            out = new PrintWriter(new OutputStreamWriter(System.out, CHARSET_NAME), true);
        }
        catch (UnsupportedEncodingException e) { System.out.println(e); }
    }
 
    private StdOut() { }
 
    public static void close() {
        out.close();
    }
 
    public static void println() {
        out.println();
    }
 
    public static void println(Object x) {
        out.println(x);
    }
 
    public static void println(boolean x) {
        out.println(x);
    }
 
    public static void println(char x) {
        out.println(x);
    }
 
    public static void println(double x) {
        out.println(x);
    }
 
    public static void println(float x) {
        out.println(x);
    }
 
    public static void println(int x) {
        out.println(x);
    }
 
    public static void println(long x) {
        out.println(x);
    }
 
    public static void println(short x) {
        out.println(x);
    }
 
    public static void println(byte x) {
        out.println(x);
    }
 
    public static void print() {
        out.flush();
    }
 
    public static void print(Object x) {
        out.print(x);
        out.flush();
    }
 
    public static void print(boolean x) {
        out.print(x);
        out.flush();
    }
 
    public static void print(char x) {
        out.print(x);
        out.flush();
    }
 
    public static void print(double x) {
        out.print(x);
        out.flush();
    }
 
    public static void print(float x) {
        out.print(x);
        out.flush();
    }
 
    public static void print(int x) {
        out.print(x);
        out.flush();
    }
 
    public static void print(long x) {
        out.print(x);
        out.flush();
    }
 
    public static void print(short x) {
        out.print(x);
        out.flush();
    }
 
    public static void print(byte x) {
        out.print(x);
        out.flush();
    }
 
    public static void printf(String format, Object... args) {
        out.printf(LOCALE, format, args);
        out.flush();
    }
 
    public static void printf(Locale locale, String format, Object... args) {
        out.printf(locale, format, args);
        out.flush();
    }
 
}