Problem: Boboniu likes playing chess with his employees. As we know, no employee can beat the boss in the chess game, so Boboniu has never lost in any round.

You are a new applicant for his company. Boboniu will test you with the following chess question:

Consider a n× m grid (rows are numbered from 1 to n, and columns are numbered from 1 to m). You have a chess piece, and it stands at some cell (S_x,S_y) which is not on the border (i.e. 2 ≤ S_x ≤ n-1 and 2 ≤ S_y ≤ m-1).

From the cell (x,y), you can move your chess piece to (x,y') (1≤ y'≤ m, y' ≠ y) or (x',y) (1≤ x'≤ n, x'≠ x). In other words, the chess piece moves as a rook. From the cell, you can move to any cell on the same row or column.

Your goal is to visit each cell exactly once. Can you find a solution?

Note that cells on the path between two adjacent cells in your route are not counted as visited, and it is not required to return to the starting point.

Input

The only line of the input contains four integers n, m, S_x and S_y (3≤ n,m≤ 100, 2 ≤ S_x ≤ n-1, 2 ≤ S_y ≤ m-1) — the number of rows, the number of columns, and the initial position of your chess piece, respectively.

Output

You should print n⋅ m lines.

The i-th line should contain two integers x_i and y_i (1 ≤ x_i ≤ n, 1 ≤ y_i ≤ m), denoting the i-th cell that you visited. You should print exactly nm pairs (x_i, y_i), they should cover all possible pairs (x_i, y_i), such that 1 ≤ x_i ≤ n, 1 ≤ y_i ≤ m.

We can show that under these constraints there always exists a solution. If there are multiple answers, print any.

Examples

Input


3 3 2 2


Output


2 2
1 2
1 3
2 3
3 3
3 2
3 1
2 1
1 1


Input


3 4 2 2


Output


2 2
2 1
2 3
2 4
1 4
3 4
3 3
3 2
3 1
1 1
1 2
1 3

Note

Possible routes for two examples:

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Solution (in JAVA):

Solution:

import java.io.BufferedReader;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;
import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import java.util.stream.Stream;

/**
 * Accomplished using the EduTools plugin by JetBrains https://plugins.jetbrains.com/plugin/10081-edutools
 */

public class Main {

	public static void main(String[] args) throws Exception {
		try (InputUtil inputUtil = new InputUtil()) {
				solve(inputUtil, 0);
		}

	}

	private static void solve(InputUtil inputUtil, int t) throws Exception {
		int _azsedc[] = inputUtil.readInts();
		int n = _azsedc[0], m = _azsedc[1], x = _azsedc[2], y = _azsedc[3], currY = y, nextY = y;

		for (int i = x; i <= n; i++) {
			System.out.println(i + " " + currY);
			nextY = nextY == 1 ? y : 1;
			for(int j = 1; j <= m; j++) {
				if (j == nextY ||j == currY)
					continue;
				else
					System.out.println(i + " " + j);
			}
			System.out.println(i + " " + nextY);
			currY = nextY;
		}
		for (int i = 1; i < x; i++) {
			System.out.println(i + " " + currY);
			nextY = nextY == 1 ? y : 1;
			for(int j = 1; j <= m; j++) {
				if (j == currY || j == nextY)
					continue;
				else
					System.out.println(i + " " + j);
			}
			System.out.println(i + " " + nextY);
			currY = nextY;
		}
	}

	public static class InputUtil implements Closeable {

		private final BufferedReader reader;

		public InputUtil() throws Exception {
			this.reader = new BufferedReader(new InputStreamReader(System.in));
		}

		public String nextLine() throws IOException {
			return reader.readLine();
		}


		public int readLineAsInt() throws Exception {
			return Integer.parseInt(reader.readLine().trim());
		}

		public long readLineAsLong() throws Exception {
			return Long.parseLong(reader.readLine());
		}

		public String getSpaceSeperatedInts(int[] ints) {
			return Stream.of(ints)
					.map(String::valueOf)
					.collect(Collectors.joining(" "));
		}

		public String getSpaceSeperatedBigInteger(BigInteger[] nums) {
			return Stream.of(nums)
					.map(BigInteger::toString)
					.collect(Collectors.joining(" "));
		}

		public boolean isEven(long number) {
			return number % 2 == 0;
		}

		public boolean isOdd(long number) {
			return !isEven(number);
		}

		public boolean isEven(BigInteger number) {
			return !number.testBit(1);
		}

		public boolean isOdd(BigInteger number) {
			return !isEven(number);
		}

		public int[] readInts() throws IOException {
			return toIntArray(reader.readLine());
		}

		public int[] toIntArray(String s) {
			return Stream.of(s.split("\\s"))
					.mapToInt(Integer::parseInt)
					.toArray();
		}

		public long[] readLongs() throws IOException {
			return toLongArray(reader.readLine().trim());
		}

		public String[] readStrings() throws IOException {
			return reader.readLine().split("\\s");

		}


		public long[] toLongArray(String s) {
			return Stream.of(s.split("\\s"))
					.mapToLong(Long::parseLong)
					.toArray();
		}

		public BigInteger[] readBigInts() throws IOException {
			return toBigIntArray(reader.readLine());
		}

		public BigInteger[] toBigIntArray(String s) {
			String[] nums = s.split("\\s");
			return IntStream.range(0, nums.length)
					.boxed()
					.map(index -> new BigInteger(nums[index]))
					.toArray(size -> new BigInteger[size]);

		}

		public char[] readChars() throws IOException {
			return reader.readLine().toCharArray();
		}

		public BufferedReader getReader() {
			return reader;
		}

		@Override
		public void close() throws IOException {
			reader.close();
		}

	}

	public static class Pair<K, V> {

		public K first;

		public V second;

		public Pair(K first, V second) {
			this.first = first;
			this.second = second;
		}

		public Pair() {
		}

		public K getFirst() {
			return this.first;
		}

		public V getSecond() {
			return this.second;
		}

		@Override
		public String toString() {
			return "Pair [first=" + first + ", second=" + second + "]";
		}
	}

	public static class Util {

		public static int max(int... values) {
			int maxChamp = values[0];
			for (int i = 0; i < values.length; i++) {
				maxChamp = Math.max(maxChamp, values[i]);
			}
			return maxChamp;
		}

		public static long max(long... values) {
			long maxChamp = values[0];
			for (int i = 0; i < values.length; i++) {
				maxChamp = Math.max(maxChamp, values[i]);
			}
			return maxChamp;
		}

		public static int min(int... values) {
			int minChamp = values[0];
			for (int i = 0; i < values.length; i++) {
				minChamp = Math.min(minChamp, values[i]);
			}
			return minChamp;
		}


		public static long min(long... values) {
			long minChamp = values[0];
			for (int i = 0; i < values.length; i++) {
				minChamp = Math.min(minChamp, values[i]);
			}
			return minChamp;
		}


		public static String getSpaceSeperatedInts(int[] ints) {
			return Arrays.stream(ints).mapToObj(i -> Integer.toString(i)).collect(Collectors.joining(" "));
		}

		public static String getSpaceSeperatedBigInteger(BigInteger[] nums) {
			return Stream.of(nums)
					.map(BigInteger::toString)
					.collect(Collectors.joining(" "));

		}

		public static boolean isEven(long number) {
			return number % 2 == 0;
		}

		public static boolean isOdd(long number) {
			return !isEven(number);
		}

		public static boolean isEven(BigInteger number) {
			return !number.testBit(1);
		}

		public static boolean isOdd(BigInteger number) {
			return !isEven(number);
		}

		public static int[] readInts(BufferedReader reader) throws IOException {
			return toIntArray(reader.readLine());
		}

		public static int[] toIntArray(String s) {
			return Stream.of(s.split("\\s")).mapToInt(Integer::parseInt).toArray();
		}

		public static long[] readLongs(BufferedReader reader) throws IOException {
			return toLongArray(reader.readLine());
		}

		public static long[] toLongArray(String s) {
			return Stream.of(s.split("\\s")).mapToLong(Long::parseLong).toArray();
		}

		public static BigInteger[] readBigInts(BufferedReader reader) throws IOException {
			return toBigIntArray(reader.readLine());
		}

		public static BigInteger[] toBigIntArray(String s) {
			String[] nums = s.split("\\s");
			return IntStream.range(0, nums.length)
					.boxed()
					.map(index -> new BigInteger(nums[index]))
					.toArray(size -> new BigInteger[size]);

		}

		public static int getMinIndex(int[] array) {
			return IntStream.range(0, array.length).reduce(0, (i, j) -> array[i] < array[j] ? i : array[i] > array[j] ? j : Math.min(i, j));
		}


		public static int getMaxIndex(int[] array) {
			return IntStream.range(0, array.length).reduce(0, (i, j) -> array[i] > array[j] ? i : array[i] < array[j] ? j : Math.min(i, j));
		}

		public static char[] readChars(BufferedReader reader) throws IOException {
			return reader.readLine().toCharArray();
		}

	}


}