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 static java.util.Collections.*;
import static java.lang.Math.*;
import static java.util.Arrays.*;

public class cfa {

    @SuppressWarnings("unused")
    private static final int MOD = (int) (1e9 + 7), MOD_FFT = 998244353;
    private static final Reader r = new Reader();
    private static final PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));
    private static final boolean thread = false;
    private static final boolean HAS_TEST_CASES = false;
    private static final int SCAN_LINE_LENGTH = 231074;

    static int n, a[], e[][], ans[], f[];
    private static ArrayList<Integer> adj[], topo;

    static void solve() throws Exception {
        int n = ni(), m = ni(), si = ni(), sj = ni();
        // int[][] vis = new int[n + 1][m + 1];
        pc1(si, sj);
        // vis[si][sj] = 1;
        for (int i = 2; i < m; i++) {
            if (i != sj) {
                pc1(si, i);
                // v//is[si][i] = 1;
            }
        }

        pc1(si, 1);
        if (si % 2 == 1) {
            pc1(si + 1, 1);
        }
        for (int i = si - 1; i > 0; --i) {
            pc1(i, 1);
        }
        for (int i = 1; i < si; i++) {
            if (i % 2 == 1) {
                for (int j = 2; j <= m; j++) {
                    pc1(i, j);
                }
            } else {
                for (int j = m; j > 1; --j) {
                    pc1(i, j);
                }
            }
        }
        if (si % 2 == 1) {
            si++;
            for (int j = 2; j <= m; j++) {
                pc1(si, j);
            }
            pc1(si - 1, m);
        } else
            pc1(si, m);
        for (int i = si + 1, c = 0; i <= n; c++, i++) {
            if (c % 2 == 1) {
                for (int j = 1; j <= m; j++) {
                    pc1(i, j);
                }
            } else {
                for (int j = m; j >= 1; --j) {
                    pc1(i, j);
                }
            }
        }
    }

    private static void pc1(int si, int sj) {
        pn(si + " " + sj);
    }

    public static void main(final String[] args) throws Exception {
        if (!thread) {
            final int testcases = HAS_TEST_CASES ? ni() : 1;
            for (int i = 1; i <= testcases; i++) {
                // out.print("Case #" + (i + 1) + ": ");
                try {
                    solve();
                } catch (final Exception e) {
                    throw e;
                    // pni("idk Exception");
                    // e.printStackTrace(System.err);
                    // System.exit(0);
                }
            }
            out.flush();
            r.close();
            out.close();
        }
    }

    @SuppressWarnings("unused")
    private static void swap(final int i, final int j) {
        final int temp = a[i];
        a[i] = a[j];
        a[j] = temp;
    }

    @SuppressWarnings("unused")
    private static int gcd(final int a, final int b) {
        if (b == 0)
            return a;
        return gcd(b, a % b);
    }

    @SuppressWarnings("unused")
    private static class Pair<T, E> implements Comparable<Pair<T, E>> {
        T fir;
        E snd;

        Pair() {
        }

        Pair(final T x, final E y) {
            this.fir = x;
            this.snd = y;
        }

        @Override
        @SuppressWarnings("unchecked")
        public int compareTo(final Pair<T, E> o) {
            final int c = ((Comparable<T>) fir).compareTo(o.fir);
            return c != 0 ? c : ((Comparable<E>) snd).compareTo(o.snd);
        }

    }

    @SuppressWarnings("unused")
    private static class pi implements Comparable<pi> {
        int fir, snd;

        pi() {
        }

        pi(final int a, final int b) {
            fir = a;
            snd = b;
        }

        public int compareTo(final pi o) {
            return fir == o.fir ? snd - o.snd : fir - o.fir;
        }

    }

    @SuppressWarnings("unused")
    private static <T> void checkV(final ArrayList<T> adj[], final int i) {
        adj[i] = adj[i] == null ? new ArrayList<>() : adj[i];
    }

    @SuppressWarnings("unused")
    private static <T> void checkV(final Vector<T> adj[], final int i) {
        adj[i] = adj[i] == null ? new Vector<>() : adj[i];
    }

    @SuppressWarnings("unused")
    private static int[] na(final int n) throws Exception {
        final int[] a = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = ni();
        }
        return a;
    }

    @SuppressWarnings("unused")
    private static int[] na1(final int n) throws Exception {
        final int[] a = new int[n + 1];
        for (int i = 1; i < a.length; i++) {
            a[i] = ni();
        }
        return a;
    }

    @SuppressWarnings("unused")
    private static String n() throws IOException {
        return r.readToken();
    }

    @SuppressWarnings("unused")
    private static String nln() throws IOException {
        return r.readLine();
    }

    private static int ni() throws IOException {
        return r.nextInt();
    }

    @SuppressWarnings("unused")
    private static long nl() throws IOException {
        return r.nextLong();
    }

    @SuppressWarnings("unused")
    private static double nd() throws IOException {
        return r.nextDouble();
    }

    @SuppressWarnings("unused")
    private static void p(final Object o) {
        out.print(o);
    }

    @SuppressWarnings("unused")
    private static void pn(final Object o) {
        out.println(o);
    }

    @SuppressWarnings("unused")
    private static void pn() {
        out.println("");
    }

    private static void pni(final Object o) {
        out.println(o);
        out.flush();
    }

    private static class Reader {
        private final int BUFFER_SIZE = 1 << 22;
        private final DataInputStream din;
        private final byte[] buffer;
        private int bufferPointer, bytesRead;
        // private StringTokenizer st;

        public Reader() {
            din = new DataInputStream(System.in);
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        @SuppressWarnings("unused")
        public Reader(final String file_name) throws IOException {
            din = new DataInputStream(new FileInputStream(file_name));
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        final byte[] buf = new byte[SCAN_LINE_LENGTH];

        public String readLine() throws IOException {
            int cnt = 0;
            int c;
            o: while ((c = read()) != -1) {
                if (c == '\n')
                    if (cnt == 0)
                        continue o;
                    else
                        break;
                buf[cnt++] = (byte) c;
            }
            return new String(buf, 0, cnt);
        }

        public String readToken() throws IOException {
            int cnt = 0;
            int c;
            o: while ((c = read()) != -1) {
                if (!(c >= 33 && c <= 126))
                    if (cnt == 0)
                        continue o;
                    else
                        break;
                buf[cnt++] = (byte) c;
            }
            return new String(buf, 0, cnt);
        }

        public int nextInt() throws IOException {
            int ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            final boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = ret * 10 + c - '0';
            } while ((c = read()) >= '0' && c <= '9');

            if (neg)
                return -ret;
            return ret;
        }

        public long nextLong() throws IOException {
            long ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            final boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = ret * 10 + c - '0';
            } while ((c = read()) >= '0' && c <= '9');
            if (neg)
                return -ret;
            return ret;
        }

        public double nextDouble() throws IOException {
            double ret = 0, div = 1;
            byte c = read();
            while (c <= ' ')
                c = read();
            final boolean neg = (c == '-');
            if (neg)
                c = read();

            do {
                ret = ret * 10 + c - '0';
            } while ((c = read()) >= '0' && c <= '9');

            if (c == '.') {
                while ((c = read()) >= '0' && c <= '9') {
                    ret += (c - '0') / (div *= 10);
                }
            }

            if (neg)
                return -ret;
            return ret;
        }

        private void fillBuffer() throws IOException {
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
            if (bytesRead == -1)
                buffer[0] = -1;
        }

        private byte read() throws IOException {
            if (bufferPointer == bytesRead)
                fillBuffer();
            return buffer[bufferPointer++];
        }

        public void close() throws IOException {
            if (din == null)
                return;
            din.close();
        }
    }

    static {
        if (thread)
            new Thread(null, new Runnable() {
                @Override
                public void run() {
                    try {
                        final int testcases = HAS_TEST_CASES ? ni() : 1;
                        for (int i = 1; i <= testcases; i++) {
                            // out.print("Case #" + (i + 1) + ": ");
                            try {
                                solve();
                            } catch (final Exception e) {
                                e.printStackTrace(System.err);
                                System.exit(-1);
                            }
                        }
                        out.flush();
                        r.close();
                        out.close();
                    } catch (final Throwable t) {
                        t.printStackTrace(System.err);
                        System.exit(-1);
                    }
                }
            }, "rec", (1L << 28)).start();
    }

    @SuppressWarnings({ "unchecked", "unused" })
    private static <T> T deepCopy(final T old) {
        try {
            return (T) deepCopyObject(old);
        } catch (final IOException | ClassNotFoundException e) {
            e.printStackTrace(System.err);
            System.exit(-1);
        }
        return null;
    }

    private static Object deepCopyObject(final Object oldObj) throws IOException, ClassNotFoundException {
        ObjectOutputStream oos = null;
        ObjectInputStream ois = null;
        try {
            final ByteArrayOutputStream bos = new ByteArrayOutputStream(); // A
            oos = new ObjectOutputStream(bos); // B
            // serialize and pass the object
            oos.writeObject(oldObj); // C
            oos.flush(); // D
            final ByteArrayInputStream bin = new ByteArrayInputStream(bos.toByteArray()); // E
            ois = new ObjectInputStream(bin); // F
            // return the new object
            return ois.readObject(); // G
        } catch (final ClassNotFoundException e) {
            pni("Exception in ObjectCloner = " + e);
            throw (e);
        } finally {
            oos.close();
            ois.close();
        }
    }

}