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{
    public static class pair{
        int x;
        int y;
    }
    public static class dpair{
        int x;
        int y;
        int z;
    }
    public static class FastScanner {
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st=new StringTokenizer("");
        public String next() {
			while (st == null || !st.hasMoreElements())
				try {
					st=new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		}
		public int nextInt() {
			return Integer.parseInt(next());
		}
		public long nextLong() {
			return Long.parseLong(next());
		}
		public int[] readArray(int n) {
			int[] a=new int[n];
			for (int i=0; i<n; i++) {
				a[i]=nextInt();
			}
			return a;
		}public double nextDouble() {
			return Double.parseDouble(next());
		}
    }
    public static void printarr(int[] arr){
        for(int i=0;i<arr.length;i++){
            System.out.print(arr[i]+" ");
        }
        System.out.println();
    }
    static HashMap<Long,Integer> map;
    public static void main(String[] args) throws IOException{
        FastScanner fs=new FastScanner();
		int t=1;//fs.nextInt();
		PrintWriter out=new PrintWriter(System.out);
		while(t-->0){
		    int n=fs.nextInt();
		    int m=fs.nextInt();
		    int sx=fs.nextInt();
		    int sy=fs.nextInt();
		    int[][] arr=new int[n+1][m+1];
		    int x=sx;
		    int y=sy;
		    arr[x][y]=1;
		    int count=1;
		    System.out.println(x+" "+y);
		    boolean z=true;
		    while(count<n*m){
		      //  System.out.println(x+" "+y+" he");
		        if(z){
		            int a=y;
		            int s=a-1;
		            while(s>0){
		                if(arr[x][s]==0){
		                    System.out.println(x+" "+s);
		                    arr[x][s]=1;
		                    y=s;
		                    count++;
		                }
		                s--;
		            }
		            s=a+1;
		            while(s<=m){
		                if(arr[x][s]==0){
		                    System.out.println(x+" "+s);
		                    arr[x][s]=1;
		                    count++;
		                    y=s;
		                  //  s++;
		                }
		                s++;
		            }
		            z=!z;
		        }else{
		            int a=x;
		            int s=a-1;
		            while(s>0){
		                if(arr[s][y]==0){
		                    System.out.println(s+" "+y);
		                    arr[s][y]=1;
		                    count++;
		                    x=s;
		                  //  s--;
		                }
		                s--;
		            }
		            s=a+1;
		            while(s<=n){
		                if(arr[s][y]==0){
		                    System.out.println(s+" "+y);
		                    arr[s][y]=1;
		                    count++;
		                    x=s;
		                  //  s++;
		                }
		                s++;
		            }
		            z=!z;
		        }
		    }
		}
        out.close();
    }
    static long fost1(dpair[] arr,pair[] a,pair[] b){
        for(int i=0;i<arr.length;i++){
            System.out.println(arr[i].x+" "+arr[i].y+" "+arr[i].z);
        }
        long max=Long.MIN_VALUE;
        int[] m=new int[arr.length];
        m[0]=arr[0].y;
        for(int i=1;i<arr.length;i++){
            m[i]=Math.max(arr[i].y,m[i-1]);
            // System.out.println(m[i]);
        }
        long[] sum=new long[arr.length];
        sum[0]=(long)arr[0].z;
        for(int i=1;i<arr.length;i++){
            sum[i]=(long)arr[i].z+sum[i-1];
            // System.out.println(sum[i]);
        }
        for(int i=0;i<arr.length;i++){
            int p1=0;
            int p2=0;
            int l=0;
            int r=a.length;
            while(l<r){
                int mid=(l+r)/2;
                if(a[mid].x<=arr[i].x){
                    l=mid+1;
                }else{
                    r=mid;
                }
            }
            while(l<a.length&&a[l].x==arr[i].x){
                l++;
            }
            if(l>=a.length){
                break;
            }
            p1=l;
            l=0;
            r=b.length;
            while(l<r){
                int mid=(l+r)/2;
                if(b[mid].x<=m[i]){
                    l=mid+1;
                }else{
                    r=mid;
                }
            }
            // System.out.println(l);
            while(l<b.length&&b[l].x==m[i]){
                l++;
            }
            if(l>=b.length){
                break;
            }
            p2=l;
            // System.out.println(p1+" "+p2);
            max=Math.max(max,sum[i]-(long)a[p1].y-(long)b[p2].y);
        }
        // System.out.println(max);
        return max;
    }
    static long fost2(dpair[] arr,pair[] a,pair[] b){
        long max=Long.MIN_VALUE;
        int[] m=new int[arr.length];
        m[0]=arr[0].x;
        for(int i=1;i<arr.length;i++){
            m[i]=Math.max(arr[i].x,m[i-1]);
        }
        long[] sum=new long[arr.length];
        sum[0]=arr[0].z;
        for(int i=1;i<arr.length;i++){
            sum[i]=(long)arr[i].z+sum[i-1];
        }
        for(int i=0;i<arr.length;i++){
            int p1=0;
            int p2=0;
            int l=0;
            int r=b.length;
            while(l<r){
                int mid=(l+r)/2;
                if(b[mid].x<=arr[i].y){
                    l=mid+1;
                }else{
                    r=mid;
                }
            }
            while(l<b.length&&b[l].x==arr[i].y){
                l++;
            }
            if(l>=b.length){
                break;
            }
            p1=l;
            l=0;
            r=a.length;
            while(l<r){
                int mid=(l+r)/2;
                if(a[mid].x<=m[i]){
                    l=mid+1;
                }else{
                    r=mid;
                }
            }
            while(l<a.length&&a[l].x==m[i]){
                l++;
            }
            if(l>=a.length){
                break;
            }
            p2=l;
            max=Math.max(max,sum[i]-(long)b[p1].y-(long)a[p2].y);
        }
        System.out.println(max);
        return max;
    }
    static long maxSubArraySum(int a[]) 
    { 
        int size = a.length; 
        long max_so_far = Long.MIN_VALUE, max_ending_here = 0; 
        int max=Integer.MIN_VALUE;
        for (int i = 0; i < size; i++) 
        { 
            max_ending_here = max_ending_here + a[i]; 
            if (max_so_far < max_ending_here) 
                max_so_far = max_ending_here; 
            if (max_ending_here < 0) 
                max_ending_here = 0; 
            max=Math.max(max,a[i]);
        } 
        if(max<0){
            return (long)0;
        }
        return max_so_far; 
    } 
    public static class Comp implements Comparator<pair>{
        public int compare(pair a,pair b){
            return a.x-b.x;
        }
    }
    public static class Comp1 implements Comparator<dpair>{
        public int compare(dpair a,dpair b){
            return a.x-b.x;
        }
    }
    public static class Comp2 implements Comparator<dpair>{
        public int compare(dpair a,dpair b){
            return a.y-b.y;
        }
    }
    public static long gcd(long a,long b){
        if (b == 0) 
        return a; 
        return gcd(b, a % b);
    }
    public static int lcm(int a,int b){
        int x=Math.max(a,b);
        int y=Math.min(a,b);
        long ans=x;
        while(ans%y!=0){
            ans+=x;
        }
        if(ans>Integer.MAX_VALUE){
            return -1;
        }
        return (int)ans;
    }
    public static long fact(int n){
        long ans=1;
        for(int i=1;i<=n;i++){
            ans*=i;
        }
        return ans;
    }
}