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.util.*;
import java.io.*;
public class Solution{

    static class Pair<A, B> {

        A parent;
        B rank;

        Pair(A parent, B rank) {
            this.rank = rank;
            this.parent = parent;
        }
    }
    static class Node {
        int index;
        int w;
        Node(int k,int l)
        {
            index=k;w=l;
        }
    }
    static class Gnode{
        int v;
        int no;
        Gnode(int g,int i)
        {
            v=g;
            no=i;
        }
    }
    static int m=1000000007;
    static int INF = 100000000;
    static long sum;
    static int count;
    public static void main(String[] args) throws IOException {
        FastReader s1 = new FastReader();
        StringBuilder sb = new StringBuilder();
        int n=s1.I();
        count=0;
        int m=s1.I();
        boolean ar[][] = new boolean[n][m];
        int x=s1.I()-1;
        int y=s1.I()-1;
        Queue<int []> que = new LinkedList<>();
        sb.append((x+1)+" "+(y+1)+"\n");
        for(int j=y+1;j<m;j++)
        {
            ar[x][j]=true;
            sb.append((x+1)+" "+(j+1)+"\n");
        }
        for(int j=y-1;j>=0;j--)
        {
            ar[x][j]=true;
            sb.append((x+1)+" "+(j+1)+"\n");
        }
        boolean flag=true;
        for(int i=x+1;i<n;i++)
        {
            if(flag)
            {
                for(int j=0;j<m;j++)
                {
                    sb.append((i+1)+" "+(j+1)+"\n");
                }
            }
            else
            {
                for(int j=m-1;j>=0;j--)
                {
                    sb.append((i+1)+" "+(j+1)+"\n");
                }
            }
            flag=(!flag);
        }
//        flag=(!flag);
        for(int i=x-1;i>=0;i--)
        {
            if(flag)
            {
                for(int j=0;j<m;j++)
                {
                    sb.append((i+1)+" "+(j+1)+"\n");
                }
            }
            else
            {
                for(int j=m-1;j>=0;j--)
                {
                    sb.append((i+1)+" "+(j+1)+"\n");
                }
            }
            flag=(!flag);
        }
        System.out.println(sb);
    }
    static boolean dfs(int ar[][],int i,int j,int n,int m,Queue<int []> que)
    {
        if(i<0 || j<0 || i>=n || j>=m || ar[i][j]!=0)
            return false;
        ar[i][j]=(++count);
        que.add(new int[]{i,j});
        if(dfs(ar,i+1,j,n,m,que)){}
        else if(dfs(ar,i,j+1,n,m,que)){}
        else if(dfs(ar,i-1,j,n,m,que)){}
        else{dfs(ar,i,j-1,n,m,que);}
        return true;
    }
       static int maxDistance(int[] arr, int n)
       {
           HashMap<Integer,Integer> hm = new HashMap<>();
           int max=Integer.MAX_VALUE;
           for(int i=0;i<n;i++)
           {
               if(hm.containsKey(arr[i]))
               {
                   int diff=i-hm.get(arr[i])-1;
                   if(diff<max)
                       max=diff;
                   hm.replace(arr[i], i);
               }
               else
               {
                   hm.put(arr[i], i);
               }
           }
           return max;
       }
    static class FastReader {

        BufferedReader br;
        StringTokenizer st;

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

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int I() {
            return Integer.parseInt(next());
        }

        long L() {
            return Long.parseLong(next());
        }

        double D() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }

    static long gcd(long a, long b) {
        if (a % b == 0) {
            return b;
        }
        return gcd(b, a % b);
    }

    static float power(float x, int y) {
        float temp;
        if (y == 0) {
            return 1;
        }
        temp = power(x, y / 2);

        if (y % 2 == 0) {
            return temp * temp;
        } else {
            if (y > 0) {
                return x * temp * temp;
            } else {
                return (temp * temp) / x;
            }
        }
    }
    static long pow(long x, long y) {
        long res = 1;
        x = x % m;
        if (x < 0) {
            x += m;
        }
        while (y > 0) {
            if ((y & 1) == 1) {
                res = (res * x) % m;
                if (res < 0) {
                    res += m;
                }
            }
            y = y >> 1;
            x = (x * x) % m;
            if (x < 0) {
                x = x + m;
            }
        }
        res = res % m;
        if (res < 0) {
            res += m;
        }
        return res;
    }

    static void sieveOfEratosthenes(int n) {
        ArrayList<Integer> prime = new ArrayList<Integer>();
        boolean Prime[] = new boolean[n + 1];
        for (int i = 2; i < n; i++) {
            Prime[i] = true;
        }

        for (int p = 2; p * p <= n; p++) {
            if (Prime[p] == true) {
                prime.add(p);
                for (int i = p * p; i <= n; i += p) {
                    Prime[i] = false;
                }
            }
        }
    }
}