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:
// package LeetCode;

import java.util.*;
import java.io.*;

public class Main {

	static class Reader {
		BufferedReader br;
		StringTokenizer st;

		public Reader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		public int nextInt() throws IOException {
			if (st == null || !st.hasMoreTokens()) {
				st = new StringTokenizer(br.readLine());
			}
			return Integer.parseInt(st.nextToken());
		}

		public float nextFloat() throws IOException {
			if (st == null || !st.hasMoreTokens()) {
				st = new StringTokenizer(br.readLine());
			}
			return Float.parseFloat(st.nextToken());
		}

		public long nextLong() throws IOException {
			if (st == null || !st.hasMoreTokens()) {
				st = new StringTokenizer(br.readLine());
			}
			return Long.parseLong(st.nextToken());
		}

		public double nextDouble() throws IOException {
			if (st == null || !st.hasMoreTokens()) {
				st = new StringTokenizer(br.readLine());
			}
			return Double.parseDouble(st.nextToken());
		}

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

		public String next() throws IOException {
			if (st == null || !st.hasMoreTokens()) {
				st = new StringTokenizer(br.readLine());
			}
			return st.nextToken();
		}
	}

	static int mod = (int) (1e9 + 7);

	public static void main(String[] args) throws IOException {
		Reader sc = new Reader();
		PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
		try {
			int t = 1;
			while (t-- > 0) {
				int n = sc.nextInt();
				int m = sc.nextInt();
				int x = sc.nextInt();
				int y = sc.nextInt();

				out.print(x);
				out.print(' ');
				out.println(y);
				for(int i=1;i<=n;i++) {
					if(i==x)
						continue;
					out.print(i);
					out.print(' ');
					out.println(y);
				}
				boolean flag = true;
				for(int j=1;j<=m;j++) {
					if(j==y)
						continue;
					if(flag) {
						for(int i=n;i>=1;i--) {
							out.print(i);
							out.print(' ');
							out.println(j);
						}
						flag = !flag;
					} else {
						for(int i=1;i<=n;i++) {
							out.print(i);
							out.print(' ');
							out.println(j);
						}
						flag = !flag;
						
					}
				}
			}
			out.flush();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	static class Pair implements Comparable<Pair> {
		long first;
		long second;

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

		@Override
		public int compareTo(Pair o) {
			if (this.first > o.first) {
				return -1;
			} else if (this.first < o.first) {
				return 1;
			} else {
				return 0;
			}
		}
	}

	static class Pair2 {
		int first, second;

		public Pair2(int first, int second) {
			this.first = first;
			this.second = second;
		}
	}
}