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.util.*;
import java.lang.*;
import java.io.*;   
import java.math.*;
public class Prac{     
    static class InputReader { 
        private final InputStream stream;
        private final byte[] buf = new byte[8192];
        private int curChar, snumChars;
        public InputReader(InputStream st) {
            this.stream = st;
        } 
        public int read() {
            if (snumChars == -1)
                throw new InputMismatchException();
            if (curChar >= snumChars) {
                curChar = 0;
                try {
                    snumChars = stream.read(buf);
                } 
                catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (snumChars <= 0)
                    return -1;
            }
            return buf[curChar++];
        }
        public int ni() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do {
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        } 
        public long nl() {
            int c = read();
            while (isSpaceChar(c)) {
            c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long res = 0;
            do {
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        } 
        public int[] nia(int n) {
            int a[] = new int[n];
            for (int i = 0; i < n; i++) {
                a[i] = ni();
            }
            return a;
        } 
        public int[] nia1(int n) {
            int a[] = new int[n+1];
            for (int i = 1; i <=n; i++) {
                a[i] = ni();
            }
            return a;
        } 
        public long[] nla(int n) {
            long a[] = new long[n];
            for (int i = 0; i < n; i++) {
                a[i] = nl();
            }
            return a;
        } 
        public long[] nla1(int n) {
            long a[] = new long[n+1];
            for (int i = 1; i <= n; i++) {
                a[i] = nl();
            }
            return a;
        } 
        public Long[] nLa(int n) {
            Long a[] = new Long[n];
            for (int i = 0; i < n; i++) {
                a[i] = nl();
            }
            return a;
        } 
        public Long[] nLa1(int n) {
            Long a[] = new Long[n+1];
            for (int i = 1; i <= n; i++) {
                a[i] = nl();
            }
            return a;
        } 
        public Integer[] nIa(int n) {
            Integer a[] = new Integer[n];
            for (int i = 0; i < n; i++) {
                a[i] = ni();
            }
            return a;
        } 
        public Integer[] nIa1(int n) {
            Integer a[] = new Integer[n+1];
            for (int i = 1; i <= n; i++) {
                a[i] = ni();
            }
            return a;
        } 
        public String rs() {
            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 String nextLine() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isEndOfLine(c));
            return res.toString();
        } 
        public boolean isSpaceChar(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        private boolean isEndOfLine(int c) {
            return c == '\n' || c == '\r' || c == -1;
        } 
    }
    public static class Key {
        private final int x, y;
        public Key(int x, int y) {
            this.x = x; this.y = y;
        }
        @Override
        public boolean equals(Object o) {
            if (this == o) return true;
            if (!(o instanceof Key)) return false;
            Key key = (Key) o;
            return x == key.x && y == key.y;
        }
        @Override
        public int hashCode() {
            int result = x;
            result = 31 * result + y;
            return result;
        }
    }
    static class Pair implements Comparable<Pair>{
            int x,y;
            Pair(int a,int b){
                    x=a;y=b;
            }
            @Override
            public int compareTo(Pair p) {
                    if(x==p.x) return y-p.y;
                    return x-p.x;
            }
    }
    static void shuffleArray(int temp[]){
        int n = temp.length;
        Random rnd = new Random();
        for(int i=0; i<n; ++i){
            int tmp = temp[i];
            int randomPos = i + rnd.nextInt(n-i);
            temp[i] = temp[randomPos];
            temp[randomPos] = tmp;
        }   
    }
    static long gcd(long a,long b){ return b==0?a:gcd(b,a%b);}
    static long lcm(long a,long b){return (a/gcd(a,b))*b;}
    static PrintWriter w = new PrintWriter(System.out);
    static long mod1=998244353L,mod=1000000007;
    //static int r[]={0,1,0,-1}, c[]={1,0,-1,0};
    
    
    public static void main(String [] args){
        InputReader sc=new InputReader(System.in); 
        int n=sc.ni(),m=sc.ni(),x=sc.ni(),y=sc.ni();
        w.println(x+" "+y);
        int j=1;
        for(;j<=m;j++){
            if(j==y)continue;
            w.println(x+" "+j);
        }
        int i=x-1;
        j=m;
        while(i!=x){
            if(j==1){
                for(;j<=m;j++)w.println(i+" "+j);
                j=m;
            }
            else{
                for(;j>=1;j--)w.println(i+" "+j);
                j=1;
            }
            i--;
            if(i==0)i=n;
        }
        w.close();
    }
}