#pragma GCC optimize("O3")

//import std;
#include "bits/stdc++.h"
#include <stdio.h>
#include "atcoder/all"
#include <boost/multiprecision/cpp_int.hpp>
using namespace boost::multiprecision;

using namespace std;
using namespace atcoder;

using ll = long long;
using ull = unsigned long long;
using mint = modint998244353;
using mint2 = modint1000000007;
const double eps = 1e-9;

#define OVERLOAD3(_1, _2, _3, call,...) call
#define REP1(i, n) for (ll i = 0; i < ll(n); ++i)
#define REP2(i, a, b) for (ll i = ll(a); i < ll(b); ++i)
#define REP(...) OVERLOAD3(__VA_ARGS__, REP2, REP1)(__VA_ARGS__)
#define RREP1(i, n) for (ll i = ll(n) - 1; i >= 0; --i)
#define RREP2(i, a, b) for (ll i = ll(a) - 1; i >= b; --i)
#define RREP(...) OVERLOAD3(__VA_ARGS__, RREP2, RREP1)(__VA_ARGS__)
#define REPE(i, c) for (auto&& i : c)
#define TCASE() ll _ttt; cin >> _ttt; while(_ttt--)

template<class... T> void COMMON_IN(T&... a) { (cin >> ... >> a); }
#define LI(...) ll __VA_ARGS__; COMMON_IN(__VA_ARGS__);
#define SI(...) string __VA_ARGS__; COMMON_IN(__VA_ARGS__);

using vl = vector<ll>; using vvl = vector<vl>; using vvvl = vector<vvl>;
#define VLI(a, n) vector<ll> a; a.assign(n, 0); for(auto& x : a) cin >> x;
#define DLI(a, n) deque<ll> a; a.assign(n, 0); for(auto& x : a) cin >> x;
#define VSI(a, n) vector<string> a; a.assign(n, ""); for(auto& x : a) cin >> x;
#define VVLI(a, n, m) vector<vector<ll>> a(n, vector<ll>(m)); for(auto& x : a) for(auto& y : x) cin >> y;
using vd = vector<double>; using pl = pair<ll, ll>; using vpl = vector<pl>; using vvpl = vector<vpl>;

struct uv { ll u; ll v; }; struct uvc { ll u; ll v; ll c = 1; };
#define VUVI(a, n) vector<uv> a; a.assign(n, {0, 0}); for(auto& x : a) {cin >> x.u >> x.v; x.u--; x.v--;}
#define VUVCI(a, n) vector<uvc> a; a.assign(n, {0, 0, 0}); for(auto& x : a) {cin >> x.u >> x.v >> x.c; x.u--; x.v--;}
vvl to_edge(const ll n, const vector<uv>& v) { vvl ret(n); for (auto& x : v) ret[x.u].emplace_back(x.v); return ret; }
vvl to_edge_d(const ll n, const vector<uv>& v) { vvl ret(n); for (auto& x : v) { ret[x.u].emplace_back(x.v); ret[x.v].emplace_back(x.u); } return ret; }
vvpl to_edge_d(const ll n, const vector<uvc>& v) { vvpl ret(n); for (auto& x : v) { ret[x.u].emplace_back(x.v, x.c); ret[x.v].emplace_back(x.u, x.c); } return ret; }

template <class T = long long> using pql = priority_queue<T>;
template <class T = long long> using pqg = priority_queue<T, vector<T>, greater<T>>;
using vm = vector<mint>; using vvm = vector<vm>;

template <class T> requires std::is_base_of_v<atcoder::internal::modint_base, T> ostream& operator<<(ostream& os, const T& v) { os << v.val(); return os; }
void yn(bool f) { std::cout << (f ? "Yes" : "No") << "\n"; };
template<class T> void ov(const T& v) { for (auto it = v.begin(); it != v.end(); it++) { if (it != v.begin()) cout << " "; cout << *it; } };
template<class T> void ovn(const T& v) { ov(v); cout << "\n"; };

const ll llhuge = 1LL << 61; //十分でかいが多少足しても溢れない数値
auto gmax(const auto& a, const auto& b) { return a > b ? a : b; };
auto gmin(const auto& a, const auto& b) { return a < b ? a : b; };
bool chmin(auto& a, const auto& b) { const auto olda = a; a = gmin(a, b); return olda != a; }
bool chmax(auto& a, const auto& b) { const auto olda = a; a = gmax(a, b); return olda != a; }
void sort(auto& v) { std::ranges::sort(v); };
void rev(auto& v) { std::ranges::reverse(v); };
template<class T> auto p_sum(const T& v) { T ret(v.size()); std::partial_sum(begin(v), end(v), ret.begin()); return ret; };
template<class T, class K = T::key_type, class V = T::mapped_type> [[nodiscard]] V myat(const T& mp, const K& key) { return mp.find(key) == mp.end() ? V() : mp.at(key); }
long long ceil(const long long a, const long long b) { return (a + b - 1) / b; }

vvl hwswap(const vvl& a) {
	ll h = a.size();
	ll w = a[0].size();
	vvl ret(w, vl(h));
	REP(i, h) {
		REP(j, w) {
			ret[j][i] = a[i][j];
		}
	}
	return ret;
}

pair<vvl, ll> c(ll h, ll w) {
	vvl ans(h, vl(w, 0));
	ll cnt = 0;
	ll hi = 0;
	if (h % 4 != 0) {
		cnt += 3;
		hi += 6;

		ans[0][0] = 1;
		ans[1][0] = 1;
		ans[2][0] = 1;
		ans[3][0] = 3;
		ans[4][0] = 3;
		ans[5][0] = 3;
		REP(j, 1, w - 1) {
			ans[0][j] = 1;
			ans[1][j] = 2;
			ans[2][j] = 1;
			ans[3][j] = 3;
			ans[4][j] = 2;
			ans[5][j] = 3;
		}
		ans[0][w - 1] = 1;
		ans[1][w - 1] = 2;
		ans[2][w - 1] = 2;
		ans[3][w - 1] = 2;
		ans[4][w - 1] = 2;
		ans[5][w - 1] = 3;
	}
	while (hi < h) {
		REP(j, w) {
			ans[hi + 0][j] = cnt + 1;
			ans[hi + 1][j] = cnt + 2;
			ans[hi + 2][j] = cnt + 1;
			ans[hi + 3][j] = cnt + 2;
		}
		ans[hi + 1][0] = cnt + 1;
		ans[hi + 2][w - 1] = cnt + 2;
		cnt += 2;
		hi += 4;
	}
	return { ans, cnt };
}

int main() {
	cin.tie(nullptr);
	ios::sync_with_stdio(false);

	LI(h, w);

	if (h == 2 || w == 2) {
		cout << -1 << "\n";
		cout << -1 << "\n";
		cout << -1 << "\n";
		return 0;
	}

	//Cは偶数辺があれば3以上、無ければ5以上
	{
		bool hws = false;
		if (h % 2 != 0 && w % 2 == 0) {
			swap(h, w);
			hws = true;
		}
		if (h % 2 == 0) {
			auto [ans, cnt] = c(h, w);

			cout << cnt << "\n";
			if (hws) {
				ans = hwswap(ans);
			}
			REP(i, ans.size()) {
				ovn(ans[i]);
			}
		}
		else {
			if (w < 5) {
				cout << -1 << "\n";
			}
			else {
				auto [tans, cnt] = c(h-1, w-2);
				
				vvl ans(h, vl(w, 0));
				REP(i, h - 1) REP(j, w - 2) {
					ans[i][j+1] = tans[i][j];
				}
				REP(i, h) {
					ans[i][0] = cnt + 1;
					ans[i][w - 1] = cnt + 1;
				}
				REP(j, w) ans[h - 1][j] = cnt + 1;
				cnt++;

				cout << cnt << "\n";
				if (hws) ans = hwswap(ans);
				REP(i, ans.size()) {
					ovn(ans[i]);
				}
			}
		}
		if (hws) swap(h, w);
	}

	{//Tは7x7が特殊ケースで、それ以外は4の倍数辺があれば4以上、無ければ7ではない辺側から5以上
		if (h < 3 || w < 3) {
			cout << -1 << "\n";
		}
		else if (h == 7 && w == 7) {
			vvl ans = {
				{1,2,2,2,2,2,2},
				{1,1,1,1,3,2,5},
				{1,3,3,3,3,2,5},
				{4,4,4,4,3,2,5},
				{6,4,5,5,5,5,5},
				{6,6,6,6,6,7,5},
				{6,7,7,7,7,7,7},
			};
			cout << 7 << "\n";
			REP(i, ans.size()) ovn(ans[i]);
		}
		else {
			bool hws = false;
			if (h == 7 || h % 4 != 0) {
				swap(h, w);
				hws = true;
			}

			if (h % 4 == 0 && w < 4) {
				cout << -1 << "\n";
			}
			else if (w < 5) {
				cout << -1 << "\n";
			}
			else {
				vvl ans(h, vl(w, 0));

				ll cnt = 0;
				ll hi = 0;
				if (h % 2 != 0) {
					cnt += 5;
					hi += 5;

					ans[0][0] = 1;
					ans[1][0] = 2;
					ans[2][0] = 3;
					ans[3][0] = 3;
					ans[4][0] = 3;
					ans[0][1] = 1;
					ans[1][1] = 2;
					ans[2][1] = 2;
					ans[3][1] = 3;
					ans[4][1] = 4;
					REP(j, 2, w - 2) {
						ans[0][j] = 1;
						ans[1][j] = 2;
						ans[2][j] = 5;
						ans[3][j] = 3;
						ans[4][j] = 4;
					}
					ans[0][w - 2] = 1;
					ans[1][w - 2] = 1;
					ans[2][w - 2] = 5;
					ans[3][w - 2] = 4;
					ans[4][w - 2] = 4;
					ans[0][w - 1] = 1;
					ans[1][w - 1] = 5;
					ans[2][w - 1] = 5;
					ans[3][w - 1] = 5;
					ans[4][w - 1] = 4;
				}
				if ((h - hi) % 4 != 0) {
					ans[hi+0][0] = 1 + cnt;
					ans[hi+1][0] = 2 + cnt;
					ans[hi+2][0] = 3 + cnt;
					ans[hi+3][0] = 3 + cnt;
					ans[hi+4][0] = 3 + cnt;
					ans[hi+5][0] = 6 + cnt;
					ans[hi+0][1] = 1 + cnt;
					ans[hi+1][1] = 2 + cnt;
					ans[hi+2][1] = 2 + cnt;
					ans[hi+3][1] = 3 + cnt;
					ans[hi+4][1] = 6 + cnt;
					ans[hi+5][1] = 6 + cnt;
					REP(j, 2, w - 2) {
						ans[hi+0][j] = 1 + cnt;
						ans[hi+1][j] = 2 + cnt;
						ans[hi+2][j] = 5 + cnt;
						ans[hi+3][j] = 3 + cnt;
						ans[hi+4][j] = 4 + cnt;
						ans[hi+5][j] = 6 + cnt;
					}
					ans[hi+0][w - 2] = 1 + cnt;
					ans[hi+1][w - 2] = 1 + cnt;
					ans[hi+2][w - 2] = 5 + cnt;
					ans[hi+3][w - 2] = 4 + cnt;
					ans[hi+4][w - 2] = 4 + cnt;
					ans[hi+5][w - 2] = 4 + cnt;
					ans[hi+0][w - 1] = 1 + cnt;
					ans[hi+1][w - 1] = 5 + cnt;
					ans[hi+2][w - 1] = 5 + cnt;
					ans[hi+3][w - 1] = 5 + cnt;
					ans[hi+4][w - 1] = 4 + cnt;
					ans[hi+5][w - 1] = 6 + cnt;

					cnt += 6;
					hi += 6;
				}
				while (hi < h) {
					ans[hi+0][0] = 1 + cnt;
					ans[hi+1][0] = 2 + cnt;
					ans[hi+2][0] = 2 + cnt;
					ans[hi+3][0] = 2 + cnt;
					ans[hi+0][1] = 1 + cnt;
					ans[hi+1][1] = 1 + cnt;
					ans[hi+2][1] = 2 + cnt;
					ans[hi+3][1] = 3 + cnt;
					REP(j, 2, w - 2) {
						ans[hi+0][j] = 1 + cnt;
						ans[hi+1][j] = 4 + cnt;
						ans[hi+2][j] = 2 + cnt;
						ans[hi+3][j] = 3 + cnt;
					}
					ans[hi+0][w - 2] = 1 + cnt;
					ans[hi+1][w - 2] = 4 + cnt;
					ans[hi+2][w - 2] = 3 + cnt;
					ans[hi+3][w - 2] = 3 + cnt;
					ans[hi+0][w - 1] = 4 + cnt;
					ans[hi+1][w - 1] = 4 + cnt;
					ans[hi+2][w - 1] = 4 + cnt;
					ans[hi+3][w - 1] = 3 + cnt;

					cnt += 4;
					hi += 4;
				}
				cout << cnt << "\n";
				if (hws) ans = hwswap(ans);
				REP(i, ans.size()) {
					ovn(ans[i]);
				}
			}
			if (hws) swap(h, w);
		}
	}

	{
		bool hws = false;
		if (h % 3 != 0) {
			swap(h, w);
			hws = true;
		}

		if (h % 3 != 0 && w < 4) {
			cout << -1 << "\n";
		}
		else {
			vvl ans(h, vl(w, 0));

			ll cnt = 0;
			ll hi = 0;
			if (h % 3 == 1) {
				ans[0][0] = 1 + cnt;
				ans[1][0] = 2 + cnt;
				ans[2][0] = 2 + cnt;
				ans[3][0] = 2 + cnt;
				REP(j, 1, w - 2) {
					ans[0][j] = 1 + cnt;
					ans[1][j] = 2 + cnt;
					ans[2][j] = 3 + cnt;
					ans[3][j] = 2 + cnt;
				}
				ans[0][w - 2] = 1 + cnt;
				ans[1][w - 2] = 1 + cnt;
				ans[2][w - 2] = 3 + cnt;
				ans[3][w - 2] = 2 + cnt;
				ans[0][w - 1] = 1 + cnt;
				ans[1][w - 1] = 3 + cnt;
				ans[2][w - 1] = 3 + cnt;
				ans[3][w - 1] = 3 + cnt;

				cnt += 3;
				hi += 4;
			}
			else if (h % 3 == 2) {
				ans[0][0] = 1 + cnt;
				ans[1][0] = 2 + cnt;
				ans[2][0] = 2 + cnt;
				ans[3][0] = 2 + cnt;
				ans[4][0] = 4 + cnt;
				REP(j, 1, w - 2) {
					ans[0][j] = 1 + cnt;
					ans[1][j] = 2 + cnt;
					ans[2][j] = 3 + cnt;
					ans[3][j] = 2 + cnt;
					ans[4][j] = 4 + cnt;
				}
				ans[0][w - 2] = 1 + cnt;
				ans[1][w - 2] = 1 + cnt;
				ans[2][w - 2] = 3 + cnt;
				ans[3][w - 2] = 4 + cnt;
				ans[4][w - 2] = 4 + cnt;
				ans[0][w - 1] = 1 + cnt;
				ans[1][w - 1] = 3 + cnt;
				ans[2][w - 1] = 3 + cnt;
				ans[3][w - 1] = 3 + cnt;
				ans[4][w - 1] = 4 + cnt;

				cnt += 4;
				hi += 5;
			}

			while (hi < h) {
				ans[hi + 0][0] = 1 + cnt;
				ans[hi + 1][0] = 1 + cnt;
				ans[hi + 2][0] = 1 + cnt;
				REP(j, 1, w - 1) {
					ans[hi + 0][j] = 1 + cnt;
					ans[hi + 1][j] = 2 + cnt;
					ans[hi + 2][j] = 1 + cnt;
				}
				ans[hi + 0][w - 1] = 2 + cnt;
				ans[hi + 1][w - 1] = 2 + cnt;
				ans[hi + 2][w - 1] = 2 + cnt;

				cnt += 2;
				hi += 3;
			}
			cout << cnt << "\n";
			if (hws) ans = hwswap(ans);
			REP(i, ans.size()) {
				ovn(ans[i]);
			}
		}
	}




}