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:

<image>

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;
import java.math.*;
import java.lang.*;
 
import static java.lang.Math.*;

public class Main implements Runnable 
{
    static class InputReader 
    {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private SpaceCharFilter filter;
        private BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        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 String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
        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 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 String readString() 
        {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do 
            {
                res.appendCodePoint(c);
                c = read();
            } 
            while (!isSpaceChar(c));
            
            return res.toString();
        }
     
        public boolean isSpaceChar(int c) 
        {
            if (filter != null)
                return filter.isSpaceChar(c);
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }
     
        public String next()
        {
            return readString();
        }
        
        public interface SpaceCharFilter
        {
            public boolean isSpaceChar(int ch);
        }
    }
			
    public static void main(String args[]) throws Exception 
    {
        new Thread(null, new Main(),"Main",1<<27).start();
    }
    static int kth_min(int arr[],int k){
        int n=arr.length;
        for(int i=n/2-1;i>=0;i--){
            min_heapify(arr,n,i);
        }
        int i;
        for(i=n-1;i>n-k-1;i--){
            int temp=arr[0];
            arr[0]=arr[i];
            arr[i]=temp;
            min_heapify(arr,i,0);
            
        }
        return arr[n-k];
    }
    
    static void min_heapify(int arr[],int n,int i){
        int min=i;
        int l=2*i+1;
        int r=2*i+2;
        
        if(l<n && arr[l]<arr[min]){
            min=l;
        }
        if(r<n && arr[r]<arr[min]){
            min=r;
        }
        if(min!=i){
            int temp=arr[i];
            arr[i]=arr[min];
            arr[min]=temp;
            min_heapify(arr,n,min);
        }
    }
    
    static void max_heapify(int arr[],int n,int i){
        int max=i;
        int l=2*i+1;
        int r=2*i+2;
        
        if(l<n && arr[l]>arr[max]){
            max=l;
        }
        if(r<n && arr[r]>arr[max]){
            max=r;
        }
        if(max!=i){
            int temp=arr[i];
            arr[i]=arr[max];
            arr[max]=temp;
            max_heapify(arr,n,max);
        }
    }
    
    public void run()
    {
        InputReader in = new InputReader(System.in);
        PrintWriter w = new PrintWriter(System.out);
		int n=in.nextInt();
		int m=in.nextInt();
		int x=in.nextInt();
		int y=in.nextInt();
		w.println(x+" "+y);
		int temp_x=x;
		int full=0;
		for(int i=1;i<=m;i++){
		    if(i==y)continue;
		    w.println(x+" "+i);
		}
		full++;
		boolean f=false;
		
		while(full<=n){
		    if(temp_x>1){
    		    if(!f){
    		        temp_x--;
    		        for(int i=m;i>0;i--)w.println(temp_x+" "+i);
    		        full++;
    		        f=!f;
    		    }
    		    else{
    		        temp_x--;
    		        for(int i=1;i<=m;i++)w.println(temp_x+" "+i);
    		        full++;
    		        f=!f;
    		    }
    		}
    		else{
    		    break;
    		}
		}
		temp_x=x;
		while(full<=n){
		    if(temp_x<n){
    		    if(!f){
    		        temp_x++;
    		        for(int i=m;i>0;i--)w.println(temp_x+" "+i);
    		        full++;
    		        f=!f;
    		    }
    		    else{
    		        temp_x++;
    		        for(int i=1;i<=m;i++)w.println(temp_x+" "+i);
    		        full++;
    		        f=!f;
    		    }
    		}
    		else{
    		    break;
    		}
		}
		
	    System.out.flush();
        w.close();
    }
}