Problem: Vasya is a Greencode wildlife preservation society proponent. One day he found an empty field nobody owned, divided it into n × m squares and decided to plant a forest there. Vasya will plant nm trees of all different heights from 1 to nm. For his forest to look more natural he wants any two trees growing in the side neighbouring squares to have the absolute value of difference in heights to be strictly more than 1. Help Vasya: make the plan of the forest planting for which this condition is fulfilled.

Input

The first line contains two space-separated integers n and m (1 ≤ n, m ≤ 100) — the number of rows and columns on Vasya's field

Output

If there's no solution, print -1. Otherwise, print n lines containing m numbers each — the trees' planting plan. In every square of the plan the height of a tree that should be planted on this square should be written. If there are several solutions to that problem, print any of them.

Examples

Input

2 3


Output

3 6 2
5 1 4


Input

2 1


Output

-1

Solution (in JAVA):

Solution:
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.io.BufferedReader;
import java.io.OutputStream;
import java.util.ArrayDeque;
import java.io.PrintWriter;
import java.util.TreeSet;
import java.util.AbstractCollection;
import java.util.StringTokenizer;
import java.util.Collection;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author Zyflair Griffane
 */
public class Main {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		PandaScanner in = new PandaScanner(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		J solver = new J();
		solver.solve(1, in, out);
		out.close();
	}
}

class J {
    public void solve(int testNumber, PandaScanner in, PrintWriter out) {
        int h = in.nextInt();
        int w = in.nextInt();
        if (h * w == 1) {
            out.println(1);
            return;
        }
        if (Math.max(h, w) < 3 || h * w <= 3) {
            out.println(-1);
            return;
        }
        int[][] res = new int[h][w];
        ArrayDeque<Integer> lst = new ArrayDeque<>();
        for (int start = 2; start >= 1; start--) {
            ArrayDeque<Integer> q = new ArrayDeque<>();
            int curr = start;
            while (curr <= h * w) {
                q.addLast(curr);
                curr += 2;
            }
            if (h == 2 && start == 1) {
                q.addFirst(q.pollLast());
            }
            lst.addAll(q);
        }
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                res[i][j] = lst.poll();
            }
            out.println(ArrayUtil.toString(res[i]));
        }
    }
}

class PandaScanner {
    public BufferedReader br;
    public StringTokenizer st;
    public InputStream in;

    public PandaScanner(InputStream in) {
        br = new BufferedReader(new InputStreamReader(this.in = in));
    }

    public String nextLine() {
        try {
            return br.readLine();
        }
        catch (Exception e) {
            return null;
        }
    }

    public String next() {
        if (st == null || !st.hasMoreTokens()) {
            st = new StringTokenizer(nextLine().trim());
            return next();
        }
        return st.nextToken();
    }

    public int nextInt() {
        return Integer.parseInt(next());
    }

    }

class ArrayUtil {

    public static<T> String toString(int[] arr) {
        StringBuilder res = new StringBuilder();
        for (int i: arr) {
            res.append(i);
            res.append(' ');
        }
        return res.toString();
    }

    }