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.io.Writer;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.OutputStreamWriter;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.IOException;
import java.io.InputStream;
import java.math.BigInteger;
import java.text.ParseException;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.ArrayList;
import java.util.InputMismatchException;
import java.util.Map.Entry;
import java.util.PriorityQueue;
import java.util.Stack;
import java.util.TreeMap;

public class Main {
	static class ProblemSolver {
		public void solveTheProblem(InputReader in, OutputWriter out) throws ParseException {
			int n = in.nextInt();
			int[] hs = new int[n];
			for (int i = 0; i < n; i ++) {
				hs[i] = in.nextInt();
			}
			for (int i = 0; i < n; i ++) {
				for (int j = 0; j < n - 1; j ++) {
					if (hs[j] > hs[j + 1]) {
						int temp = hs[j];
						hs[j] = hs[j + 1];
						hs[j + 1] = temp;
						out.println(j + 1, j + 2);
					}	
				}
			}
		}
	}

	public static void main(String[] args) throws FileNotFoundException, ParseException {
		// InputStream inputStream = new FileInputStream("input.txt");
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		OutputWriter out = new OutputWriter(outputStream);
		ProblemSolver problemSolver = new ProblemSolver();
		problemSolver.solveTheProblem(in, out);
		out.flush();
		out.close();
	}

	static class InputReader {

		private InputStream stream;
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;
		private SpaceCharFilter filter;

		public InputReader(InputStream stream) {
			this.stream = stream;
		}

		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++];
		}

		public int peek() {
			if (numChars == -1) {
				return -1;
			}
			if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = stream.read(buf);
				} catch (IOException e) {
					return -1;
				}
				if (numChars <= 0) {
					return -1;
				}
			}
			return buf[curChar];
		}

		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 nextString() {
			int c = read();
			while (isSpaceChar(c)) {
				c = read();
			}
			StringBuilder res = new StringBuilder();
			do {
				if (Character.isValidCodePoint(c)) {
					res.appendCodePoint(c);
				}
				c = read();
			} while (!isSpaceChar(c));
			return res.toString();
		}

		public boolean isSpaceChar(int c) {
			if (filter != null) {
				return filter.isSpaceChar(c);
			}
			return isWhitespace(c);
		}

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

		private String readLine0() {
			StringBuilder buf = new StringBuilder();
			int c = read();
			while (c != '\n' && c != -1) {
				if (c != '\r') {
					buf.appendCodePoint(c);
				}
				c = read();
			}
			return buf.toString();
		}

		public String readLine() {
			String s = readLine0();
			while (s.trim().length() == 0) {
				s = readLine0();
			}
			return s;
		}

		public String readLine(boolean ignoreEmptyLines) {
			if (ignoreEmptyLines) {
				return readLine();
			} else {
				return readLine0();
			}
		}

		public BigInteger readBigInteger() {
			try {
				return new BigInteger(nextString());
			} catch (NumberFormatException e) {
				throw new InputMismatchException();
			}
		}

		public char nextCharacter() {
			int c = read();
			while (isSpaceChar(c)) {
				c = read();
			}
			return (char) c;
		}

		public double nextDouble() {
			int c = read();
			while (isSpaceChar(c)) {
				c = read();
			}
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			double res = 0;
			while (!isSpaceChar(c) && c != '.') {
				if (c == 'e' || c == 'E') {
					return res * Math.pow(10, nextInt());
				}
				if (c < '0' || c > '9') {
					throw new InputMismatchException();
				}
				res *= 10;
				res += c - '0';
				c = read();
			}
			if (c == '.') {
				c = read();
				double m = 1;
				while (!isSpaceChar(c)) {
					if (c == 'e' || c == 'E') {
						return res * Math.pow(10, nextInt());
					}
					if (c < '0' || c > '9') {
						throw new InputMismatchException();
					}
					m /= 10;
					res += (c - '0') * m;
					c = read();
				}
			}
			return res * sgn;
		}

		public boolean isExhausted() {
			int value;
			while (isSpaceChar(value = peek()) && value != -1) {
				read();
			}
			return value == -1;
		}

		public String next() {
			return nextString();
		}

		public SpaceCharFilter getFilter() {
			return filter;
		}

		public void setFilter(SpaceCharFilter filter) {
			this.filter = filter;
		}

		public interface SpaceCharFilter {
			public boolean isSpaceChar(int ch);
		}

		public int[] nextIntArray(int n) {
			int[] array = new int[n];
			for (int i = 0; i < n; ++i)
				array[i] = nextInt();
			return array;
		}

		public int[] nextSortedIntArray(int n) {
			int array[] = nextIntArray(n);
			Arrays.sort(array);
			return array;
		}

		public int[] nextSumIntArray(int n) {
			int[] array = new int[n];
			array[0] = nextInt();
			for (int i = 1; i < n; ++i)
				array[i] = array[i - 1] + nextInt();
			return array;
		}

		public long[] nextLongArray(int n) {
			long[] array = new long[n];
			for (int i = 0; i < n; ++i)
				array[i] = nextLong();
			return array;
		}

		public long[] nextSumLongArray(int n) {
			long[] array = new long[n];
			array[0] = nextInt();
			for (int i = 1; i < n; ++i)
				array[i] = array[i - 1] + nextInt();
			return array;
		}

		public long[] nextSortedLongArray(int n) {
			long array[] = nextLongArray(n);
			Arrays.sort(array);
			return array;
		}

		public int[][] nextIntMatrix(int n, int m) {
			int[][] matrix = new int[n][m];
			for (int i = 0; i < n; ++i)
				for (int j = 0; j < m; ++j)
					matrix[i][j] = nextInt();
			return matrix;
		}

		public int[][] nextIntMatrix(int n) {
			return nextIntMatrix(n, n);
		}

		public long[][] nextLongMatrix(int n, int m) {
			long[][] matrix = new long[n][m];
			for (int i = 0; i < n; ++i)
				for (int j = 0; j < m; ++j)
					matrix[i][j] = nextLong();
			return matrix;
		}

		public long[][] nextLongMatrix(int n) {
			return nextLongMatrix(n, n);
		}

		public char[][] nextCharMatrix(int n, int m) {
			char[][] matrix = new char[n][m];
			for (int i = 0; i < n; ++i)
				matrix[i] = next().toCharArray();
			return matrix;
		}

		public char[][] nextCharMatrix(int n) {
			return nextCharMatrix(n, n);
		}
	}

	static class OutputWriter {
		private final PrintWriter writer;

		public OutputWriter(OutputStream outputStream) {
			writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
		}

		public OutputWriter(Writer writer) {
			this.writer = new PrintWriter(writer);
		}

		public void print(Object... objects) {
			for (int i = 0; i < objects.length; i++) {
				if (i != 0) {
					writer.print(' ');
				}
				writer.print(objects[i]);
			}
		}

		public void print(int[] array) {
			for (int i = 0; i < array.length; i++) {
				if (i != 0) {
					writer.print(' ');
				}
				writer.print(array[i]);
			}
		}

		public void print(double[] array) {
			for (int i = 0; i < array.length; i++) {
				if (i != 0) {
					writer.print(' ');
				}
				writer.print(array[i]);
			}
		}

		public void print(long[] array) {
			for (int i = 0; i < array.length; i++) {
				if (i != 0) {
					writer.print(' ');
				}
				writer.print(array[i]);
			}
		}

		public void print(char[] array) {
			for (int i = 0; i < array.length; i++) {
				if (i != 0) {
					writer.print(' ');
				}
				writer.print(array[i]);
			}
		}

		public void print(String[] array) {
			for (int i = 0; i < array.length; i++) {
				if (i != 0) {
					writer.print(' ');
				}
				writer.print(array[i]);
			}
		}

		public void print(int[][] matrix) {
			for (int i = 0; i < matrix.length; ++i) {
				println(matrix[i]);
			}
		}

		public void print(double[][] matrix) {
			for (int i = 0; i < matrix.length; ++i) {
				println(matrix[i]);
			}
		}

		public void print(long[][] matrix) {
			for (int i = 0; i < matrix.length; ++i) {
				println(matrix[i]);
			}
		}

		public void print(char[][] matrix) {
			for (int i = 0; i < matrix.length; ++i) {
				println(matrix[i]);
			}
		}

		public void print(String[][] matrix) {
			for (int i = 0; i < matrix.length; ++i) {
				println(matrix[i]);
			}
		}

		public void println(int[] array) {
			print(array);
			writer.println();
		}

		public void println(double[] array) {
			print(array);
			writer.println();
		}

		public void println(long[] array) {
			print(array);
			writer.println();
		}

		public void println(char[] array) {
			print(array);
			writer.println();
		}

		public void println(String[] array) {
			print(array);
			writer.println();
		}

		public void println() {
			writer.println();
		}

		public void println(Object... objects) {
			print(objects);
			writer.println();
		}

		public void print(char i) {
			writer.print(i);
		}

		public void println(char i) {
			writer.println(i);
		}

		public void printf(String format, Object... objects) {
			writer.printf(format, objects);
		}

		public void close() {
			writer.close();
		}

		public void flush() {
			writer.flush();
		}

		public void print(long i) {
			writer.print(i);
		}

		public void println(long i) {
			writer.println(i);
		}

		public void print(int i) {
			writer.print(i);
		}

		public void println(int i) {
			writer.println(i);
		}

		public void separateLines(int[] array) {
			for (int i : array) {
				println(i);
			}
		}
	}
}