#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define rep1(i,n) for(int i = 1; i <= (n); ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
#define srep(i,s,t) for (int i = s; i < (t); ++i)
#define rng(a) a.begin(),a.end()
#define rrng(a) a.rbegin(),a.rend()
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define em emplace
#define pob pop_back
#define sz(x) (int)(x).size()
#define pcnt __builtin_popcountll
#define snuke srand((unsigned)clock()+(unsigned)time(NULL));
#define newline puts("")
#define vc vector
using namespace std;
template<class T> using vv = vc<vc<T>>;
template<class T> using PQ = priority_queue<T,vc<T>,greater<T>>;
using uint = unsigned; using ull = unsigned long long;
using vi = vc<int>; using vvi = vv<int>; using vvvi = vv<vi>;
using ll = long long; using vl = vc<ll>; using vvl = vv<ll>; using vvvl = vv<vl>;
using P = pair<int,int>; using vp = vc<P>; using vvp = vv<P>; using LP = pair<ll,ll>;
int geti(){int x;scanf("%d",&x);return x;}
vi pm(int n, int s=0) { vi a(n); iota(rng(a),s); return a;}
template<class T1,class T2>istream& operator>>(istream&i,pair<T1,T2>&v){return i>>v.fi>>v.se;}
template<class T1,class T2>ostream& operator<<(ostream&o,const pair<T1,T2>&v){return o<<v.fi<<","<<v.se;}
template<class T>istream& operator>>(istream&i,vc<T>&v){rep(j,sz(v))i>>v[j];return i;}
template<class T>string join(const T&v,const string&d=""){stringstream s;rep(i,sz(v))(i?s<<d:s)<<v[i];return s.str();}
template<class T>ostream& operator<<(ostream&o,const vc<T>&v){if(sz(v))o<<join(v," ");return o;}
template<class T>void vin(vc<T>&a){int n;cin>>n;a=vc<T>(n);cin>>a;}
template<class T>void vin(vv<T>&a){int n,m;cin>>n>>m;a=vv<T>(n,vc<T>(m));cin>>a;}
template<class T1,class T2>void operator--(pair<T1,T2>&a,int){a.fi--;a.se--;}
template<class T1,class T2>void operator++(pair<T1,T2>&a,int){a.fi++;a.se++;}
template<class T>void operator--(vc<T>&a,int){for(T&x:a)x--;}
template<class T>void operator++(vc<T>&a,int){for(T&x:a)x++;}
template<class T1,class T2>void operator+=(vc<T1>&a,T2 b){for(T1&x:a)x+=b;}
template<class T1,class T2>void operator-=(vc<T1>&a,T2 b){for(T1&x:a)x-=b;}
template<class T1,class T2>void operator*=(vc<T1>&a,T2 b){for(T1&x:a)x*=b;}
template<class T1,class T2>void operator/=(vc<T1>&a,T2 b){for(T1&x:a)x/=b;}
template<class T>void operator+=(vc<T>&a,const vc<T>&b){a.insert(a.end(),rng(b));}
template<class T1,class T2>pair<T1,T2>operator+(const pair<T1,T2>&a,const pair<T1,T2>&b){return {a.fi+b.fi,a.se+b.se};}
template<class T1,class T2>pair<T1,T2>operator-(const pair<T1,T2>&a,const pair<T1,T2>&b){return {a.fi-b.fi,a.se-b.se};}
template<class T>pair<T,T>operator*(const pair<T,T>&a,T b){return {a.fi*b,a.se*b};}
template<class T1,class T2>bool mins(T1& x,const T2&y){if(y<x){x=y;return true;}else return false;}
template<class T1,class T2>bool maxs(T1& x,const T2&y){if(x<y){x=y;return true;}else return false;}
template<class T>T min(const vc<T>&a){return *min_element(rng(a));}
template<class T>T max(const vc<T>&a){return *max_element(rng(a));}
template<class Tx,class Ty>Tx dup(Tx x, Ty y){return (x+y-1)/y;}
template<class T>ll suma(const vc<T>&a){ll s=0;for(auto&&x:a)s+=x;return s;}
template<class T>ll suma(const vv<T>&a){ll s=0;for(auto&&x:a)s+=suma(x);return s;}
template<class T>void uni(T&a){sort(rng(a));a.erase(unique(rng(a)),a.end());}
template<class T>void prepend(vc<T>&a,const T&x){a.insert(a.begin(),x);}
const double eps = 1e-10;
const ll LINF = 1001002003004005006ll;
const int INF = 1001001001;
#define dame { cout<<"-1"<<'\n'; return;}
#define yes { cout<<"Yes"<<'\n'; return;}
#define no { cout<<"No"<<'\n'; return;}
#define yn {cout<<"Yes"<<'\n';}else{cout<<"No"<<'\n';}
#define rtn(x) { cout<<(x)<<'\n'; return;} // flush!
template<typename T> vc<T> trans(const vc<T>&a) {
  if (!sz(a)) return {};
  int h = sz(a), w = sz(a[0]);
  vc<T> r(w,T(h,0));
  rep(i,w)rep(j,h) r[i][j] = a[j][i];
  return r;
}

struct Solver {
  int getk(vvi& a) {
    int k = 0;
    rep(i,sz(a))rep(j,sz(a[i])) maxs(k,a[i][j]);
    return k;
  }
  vvi fu(int h, int w) {
    if (min(h,w) == 2) return {};
    if (h%2 == 0) {
      vvi a(h);
      a[0] = vi(w,1);
      int k = 1;
      for (int i = 1; i < h-1; i += 2, k++) {
        if (k%2) {
          a[i] = vi(w,k+1); a[i].back() = k;
          a[i+1] = vi(w,k); a[i+1][0] = k+1;
        } else {
          a[i] = vi(w,k+1); a[i][0] = k;
          a[i+1] = vi(w,k); a[i+1].back() = k+1;
        }
      }
      a[h-1] = vi(w,k);
      return a;
    }
    if (w%2 == 0) {
      vvi a = fu(w,h);
      return trans(a);
    }
    if (min(h,w) == 3) return {};

    vvi a = fu(h-1,w-2);
    int k = getk(a);
    k++;
    a.pb(vi(w,k));
    rep(i,h-1) prepend(a[i],k), a[i].pb(k);
    return a;
  }
  vvi ft(int h, int w) {
    if (h > w) {
      vvi a = ft(w,h);
      return trans(a);
    }
    if (h == 2) return {};
    if (h == 3) {
      if (w < 6) return {};
      vvi a;
      a.pb((vi){1,1,1});
      a.pb((vi){2,1,3});
      a.pb((vi){2,2,3});
      a.pb((vi){2,3,3});
      rep(i,w-5) a.pb((vi){2,4,3});
      a.pb((vi){4,4,4});
      return trans(a);
    }
    if (h == 4) {
      vvi a;
      a.pb((vi){1,1,1,2});
      a.pb((vi){3,1,2,2});
      rep(i,w-4) a.pb((vi){3,1,4,2});
      a.pb((vi){3,3,4,2});
      a.pb((vi){3,4,4,4});
      return trans(a);
    }
    if (h == 5) {
      vvi a;
      a.pb((vi){1,1,1,1,1});
      a.pb((vi){3,1,2,2,2});
      rep(i,w-4) a.pb((vi){3,1,4,2,5});
      a.pb((vi){3,3,4,5,5});
      a.pb((vi){3,4,4,4,5});
      return trans(a);
    }
    vvi a = ft(h-3,w);
    int k = getk(a);
    vvi b = ft(3,w);
    b += k;
    a += b;
    return a;
  }
  vvi fut(int h, int w) {
    if (h > w) {
      vvi a = fut(w,h);
      return trans(a);
    }
    if (h == 2) return {};
    if (h == 3) {
      vvi a;
      a.pb((vi){1,1,1});
      rep(i,w-2) a.pb((vi){2,1,2});
      a.pb((vi){2,2,2});
      return trans(a);
    }
    if (h == 4) {
      vvi a;
      a.pb((vi){1,1,1,2});
      rep(i,w-3) a.pb((vi){1,3,1,2});
      a.pb((vi){1,3,2,2});
      a.pb((vi){3,3,3,2});
      return trans(a);
    }
    if (h == 5) {
      vvi a;
      a.pb((vi){3,1,1,1,2});
      rep(i,w-3) a.pb((vi){3,1,4,1,2});
      a.pb((vi){3,3,4,2,2});
      a.pb((vi){3,4,4,4,2});
      return trans(a);
    }
    vvi a = fut(h-3,w);
    int k = getk(a);
    vvi b = fut(3,w);
    b += k;
    a += b;
    return a;
  }
  void solve() {
    int h,w;
    scanf("%d%d",&h,&w);
    rep(ti,3) {
      vvi a;
      if (ti == 0) a = fu(h,w);
      if (ti == 1) a = ft(h,w);
      if (ti == 2) a = fut(h,w);
      if (sz(a)) {
        int k = getk(a);
        cout<<k<<endl;
        rep(i,h) cout<<a[i]<<endl;
      } else cout<<-1<<endl;
    }
  }
};

int main() {
  // cin.tie(nullptr); ios::sync_with_stdio(false);
  int ts = 1;
  // cin >> ts;
  rep1(ti,ts) {
    Solver solver;
    solver.solve();
  }
  return 0;
}