using Lib;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Diagnostics.Contracts;
using System.IO;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using static Lib.OutputLib;
public class Solver
{
    const bool MultiTestCase = false;
    void Solve()
    {
        int h = ri, w = ri;
        CalcC(h, w);
        CalcT(h, w);
        CalcCT(h, w);
    }

    void CalcC(int h, int w)
    {
        int n = Math.Max(h, w);
        var f = new bool[n + 1, n + 1];
        for (int i = 0; i <= n; i++) f[i, 0] = true;
        for (int j = 0; j <= n; j++) f[0, j] = true;
        for (int i = 1; i <= n; i++)
            for (int j = 1; j <= n; j++)
            {
                if (i >= 4 && i % 2 == 0 && j >= 3) f[i, j] |= true;
                if (i >= 3 && j >= 4 && j % 2 == 0) f[i, j] |= true;

                if (i > 1 && j > 2) f[i, j] |= f[i - 1, j - 2];
                if (i > 2 && j > 1) f[i, j] |= f[i - 2, j - 1];
            }

        var a = new int[h, w];
        int cnt = 0;
        void calc(int h, int w, Action<int, int, int> set)
        {
            if (h == 0 || w == 0) return;
            if (!f[h, w])
            {
                cnt = -IINF;
                return;
            }
            if (h >= 4 && h % 2 == 0 && w >= 3)
            {
                while (h >= 6)
                {
                    for (int j = 0; j < w; j++)
                    {
                        set(0, j, cnt + 1);
                        set(1, j, cnt + 2);
                        set(2, j, cnt + 1);
                        set(3, j, cnt + 3);
                        set(4, j, cnt + 2);
                        set(5, j, cnt + 3);
                    }
                    set(1, 0, cnt + 1);
                    set(2, w - 1, cnt + 2);
                    set(3, w - 1, cnt + 2);
                    set(4, 0, cnt + 3);
                    cnt += 3;
                    h -= 6;
                }
                if (h >= 4)
                {
                    for (int j = 0; j < w; j++)
                    {
                        set(0, j, cnt + 1);
                        set(1, j, cnt + 2);
                        set(2, j, cnt + 1);
                        set(3, j, cnt + 2);
                    }
                    set(1, 0, cnt + 1);
                    set(2, w - 1, cnt + 2);
                    cnt += 2;
                    h -= 4;
                }
            }
            else if (h > 1 && w > 2 && f[h - 1, w - 2])
            {
                for (int i = 0; i < h; i++) set(i, 0, cnt + 1);
                for (int i = 0; i < h; i++) set(i, w - 1, cnt + 1);
                for (int j = 0; j < w; j++) set(0, j, cnt + 1);
                cnt += 1;
                calc(h - 1, w - 2, (i, j, v) => set(i + 1, j + 1, v));
            }
            else
            {
                calc(w, h, (i, j, v) => set(j, i, v));
            }
        }
        calc(h, w, (i, j, v) => a[i, j] = v);
        if (cnt < 0)
        {
            Contract.Assert(cnt >= 0);
            Write(-1);
        }
        else
        {
            Write(cnt);
            WriteMat(a);
        }
    }
    void CalcT(int h, int w)
    {
        int n = Math.Max(h, w);
        var f = new bool[n + 1, n + 1];
        for (int i = 0; i <= n; i++) f[i, 0] = true;
        for (int j = 0; j <= n; j++) f[0, j] = true;
        for (int i = 1; i <= n; i++)
            for (int j = 1; j <= n; j++)
            {
                if (i >= 4 && j >= 4)
                {
                    f[i, j] |= f[i - 4, j];
                    f[i, j] |= f[i, j - 4];
                }
                if (i > 2 && j > 3) f[i, j] |= f[i - 2, j - 3];
                if (i > 3 && j > 2) f[i, j] |= f[i - 3, j - 2];
            }

        var a = new int[h, w];
        int cnt = 0;
        void calc(int h, int w, Action<int, int, int> set)
        {
            if (h == 0 || w == 0) return;
            if (!f[h, w])
            {
                cnt = -IINF;
                return;
            }
            if (h > 3 && w > 2 && f[h - 3, w - 2])
            {
                for (int i = 0; i < h; i++) set(i, w - 1, cnt + 3);
                for (int j = 0; j < w; j++) set(2, j, cnt + 3);
                for (int j = 0; j < w; j++) set(0, j, cnt + 1);
                for (int i = 0; i < h; i++) set(i, 0, cnt + 2);
                for (int j = 0; j < w - 2; j++) set(1, j, cnt + 2);
                set(1, w - 2, cnt + 1);
                cnt += 3;
                calc(h - 3, w - 2, (i, j, v) => set(i + 3, j + 1, v));
            }
            else if (h >= 4 && f[h - 4, w])
            {
                for (int i = 0; i < h - 1; i++) set(i, 0, cnt + 1);
                for (int j = 0; j < w - 2; j++) set(1, j, cnt + 1);
                for (int j = 1; j < w; j++) set(0, j, cnt + 2);
                for (int i = 0; i < h - 2; i++) set(i, w - 2, cnt + 2);
                for (int i = 1; i < h; i++) set(i, w - 1, cnt + 3);
                for (int j = 2; j < w; j++) set(h - 2, j, cnt + 3);
                for (int j = 0; j < w - 1; j++) set(h - 1, j, cnt + 4);
                for (int i = 2; i < h; i++) set(i, 1, cnt + 4);
                cnt += 4;
            }
            else
            {
                calc(w, h, (i, j, v) => set(j, i, v));
            }
        }
        calc(h, w, (i, j, v) => a[i, j] = v);
        if (cnt < 0)
        {
            Write(-1);
        }
        else
        {
            Write(cnt);
            WriteMat(a);
        }
    }
    void CalcCT(int h, int w)
    {
        var a = new int[h, w];
        int cnt = 0;

        void calc(int h, int w, Action<int, int, int> set)
        {
            if (h <= 2 || w <= 2)
            {
                cnt = -IINF;
                return;
            }
            if (h > w)
            {
                calc(w, h, (i, j, v) => set(j, i, v));
                return;
            }
            if (h == 3)
            {
                for (int j = 0; j < w; j++)
                {
                    set(0, j, cnt + 1);
                    set(1, j, cnt + 2);
                    set(2, j, cnt + 1);
                }
                set(0, w - 1, cnt + 2);
                set(1, 0, cnt + 1);
                set(2, w - 1, cnt + 2);
                cnt += 2;
            }
            else if (h == 4)
            {
                for (int j = 0; j < w; j++)
                {
                    set(0, j, cnt + 1);
                    set(1, j, cnt + 2);
                    set(2, j, cnt + 3);
                    set(3, j, cnt + 2);
                }
                set(1, w - 2, cnt + 1);
                set(1, w - 1, cnt + 3);
                set(2, 0, cnt + 2);
                set(3, w - 1, cnt + 3);
                cnt += 3;
            }
            else
            {
                for (int j = 0; j < w; j++) set(0, j, cnt + 1);
                for (int i = 0; i < h; i++) set(i, 0, cnt + 1);
                for (int j = 0; j < w; j++) set(h - 1, j, cnt + 1);
                cnt += 1;
                calc(h - 2, w - 1, (i, j, v) => set(i + 1, j + 1, v));
            }
        }
        calc(h, w, (i, j, v) => a[i, j] = v);
        if (cnt < 0)
        {
            Write(-1);
        }
        else
        {
            Write(cnt);
            WriteMat(a);
        }
    }

#pragma warning disable CS0162, CS8618
    public Solver() { if (!MultiTestCase) Solve(); else for (int t = ri; t > 0; t--) Solve(); }
#pragma warning restore CS0162, CS8618

    const int IINF = 1 << 30;
    const long INF = 1L << 60;
    int ri { [MethodImpl(256)] get => (int)sc.Integer(); }
    long rl { [MethodImpl(256)] get => sc.Integer(); }
    uint rui { [MethodImpl(256)] get => (uint)sc.UInteger(); }
    ulong rul { [MethodImpl(256)] get => sc.UInteger(); }
    double rd { [MethodImpl(256)] get => sc.Double(); }
    string rs { [MethodImpl(256)] get => sc.Scan(); }
    string rline { [MethodImpl(256)] get => sc.Line(); }
    public StreamScanner sc = new StreamScanner(Console.OpenStandardInput());
    void ReadArray(out int[] a, int n) { a = new int[n]; for (int i = 0; i < a.Length; i++) a[i] = ri; }
    void ReadArray(out long[] a, int n) { a = new long[n]; for (int i = 0; i < a.Length; i++) a[i] = rl; }
    void ReadArray<T>(out T[] a, int n, Func<T> read) { a = new T[n]; for (int i = 0; i < a.Length; i++) a[i] = read(); }
    void ReadArray<T>(out T[] a, int n, Func<int, T> read) { a = new T[n]; for (int i = 0; i < a.Length; i++) a[i] = read(i); }
}

static class Program
{
    static public void Main(string[] args)
    {
        SourceExpander.Expander.Expand();
        Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false });
        new Solver();
        Console.Out.Flush();
    }
}
#region Expanded by https://github.com/kzrnm/SourceExpander
namespace Lib { public partial class StreamScanner { public StreamScanner(Stream stream) { str = stream; } private readonly Stream str; private readonly byte[] buf = new byte[1024]; private int len, ptr; public bool isEof = false; public bool IsEndOfStream { get { return isEof; } } [MethodImpl(256)] private byte Read() { if (isEof) throw new EndOfStreamException(); if (ptr >= len) { ptr = 0; if ((len = str.Read(buf, 0, 1024)) <= 0) { isEof = true; return 0; } } return buf[ptr++]; } [MethodImpl(256)] public char Char() { byte b; do b = Read(); while (b < 33 || 126 < b); return (char)b; } [MethodImpl(256)] public string Line() { var sb = new StringBuilder(); for (var b = Char(); b != 10 && !isEof; b = (char)Read()) sb.Append(b); return sb.ToString(); } [MethodImpl(256)] public string Scan() { var sb = new StringBuilder(); for (var b = Char(); b >= 33 && b <= 126; b = (char)Read()) sb.Append(b); return sb.ToString(); } [MethodImpl(256)] public long Integer() { long ret = 0; var ng = false; byte b; do b = Read(); while (b != '-' && (b < '0' || '9' < b)); if (b == '-') { ng = true; b = Read(); } for (; '0' <= b && b <= '9'; b = Read()) ret = ret * 10 + (b ^ '0'); return ng ? -ret : ret; } [MethodImpl(256)] public ulong UInteger() { ulong ret = 0; byte b; do b = Read(); while (b < '0' || '9' < b); for (; '0' <= b && b <= '9'; b = Read()) ret = ret * 10 + (ulong)(b ^ '0'); return ret; } [MethodImpl(256)] public double Double() => double.Parse(Scan()); } }
namespace Lib { public static class OutputLib { [MethodImpl(256)] public static void WriteJoin<T>(string s, IEnumerable<T> t) => Console.WriteLine(string.Join(s, t)); [MethodImpl(256)] public static void WriteMat<T>(T[,] a, string sep = " ") { int sz1 = a.GetLength(0), sz2 = a.GetLength(1); var b = new T[sz2]; for (int i = 0; i < sz1; i++) { for (int j = 0; j < sz2; j++) b[j] = a[i, j]; WriteJoin(sep, b); } } [MethodImpl(256)] public static void WriteMat<T>(T[][] a, string sep = " ") { foreach (var ar in a) WriteJoin(sep, ar); } [MethodImpl(256)] public static void WriteMat<T>(T[][] a, Func<T, string> map, string sep = " ") { foreach (var ar in a) WriteJoin(sep, ar.Select(x => map(x))); } [MethodImpl(256)] public static void Write(object t) => Console.WriteLine(t.ToString()); [MethodImpl(256)] public static void Write(params object[] arg) => Console.WriteLine(string.Join(" ", arg.Select(x => x.ToString()))); [MethodImpl(256)] public static void Write(string str) => Console.WriteLine(str); [MethodImpl(256)] public static void WriteFlush(object t) { Console.WriteLine(t.ToString()); Console.Out.Flush(); } [MethodImpl(256)] public static void WriteError(object t) => Console.Error.WriteLine(t.ToString()); [MethodImpl(256)] public static void Flush() => Console.Out.Flush(); [MethodImpl(256)] public static void YN(bool t) => Console.WriteLine(t ? "YES" : "NO"); [MethodImpl(256)] public static void Yn(bool t) => Console.WriteLine(t ? "Yes" : "No"); [MethodImpl(256)] public static void yn(bool t) => Console.WriteLine(t ? "yes" : "no"); [MethodImpl(256)] public static void DeleteLine() => Console.Write("\x1b[1A\x1b[2K"); [MethodImpl(256)] public static void ProgressBar(long now, long total, int blocks = 50) { int x = (int)((2 * now * blocks + 1) / (2 * total)); Console.Write($"\x1b[G[\x1b[42m{string.Concat(Enumerable.Repeat("_", x))}\x1b[0m{string.Concat(Enumerable.Repeat("_", blocks - x))}] : {now} / {total}"); } } }
namespace SourceExpander { public class Expander { [Conditional("EXP")] public static void Expand(string inputFilePath = null, string outputFilePath = null, bool ignoreAnyError = true) { } public static string ExpandString(string inputFilePath = null, bool ignoreAnyError = true) { return ""; } } }
#endregion Expanded by https://github.com/kzrnm/SourceExpander