#include <bits/stdc++.h>
using namespace std;
const long double EPS = 1e-10;
const long long MOD = 1e9 + 7;
const long double PI = 3.1415926535897932384626433832795028841;
long long powmod(long long a, long long b) {
  long long res = 1;
  a %= MOD;
  for (; b; b >>= 1) {
    if (b & 1) res = res * a % MOD;
    a = a * a % MOD;
  }
  return res;
}
ostream& operator<<(std::ostream& stream, const long long* arr) {
  int i = 0;
  cout << "{";
  while (arr[i] != INT_MAX) {
    cout << arr[i];
    if (arr[i + 1] != INT_MAX) cout << ",";
    i++;
  }
  cout << "}";
  return stream;
}
ostream& operator<<(std::ostream& stream, const vector<int> vec) {
  cout << "{";
  for (int i = 0; i < vec.size(); i++) {
    cout << vec[i];
    if (i != vec.size() - 1) cout << ",";
  }
  cout << "}";
  return stream;
}
ostream& operator<<(std::ostream& stream,
                    const pair<long long, long long>& vec) {
  cout << "(" << vec.first << ',' << vec.second << ")";
  return stream;
}
template <class T>
struct segtree_t {
  vector<T> t, lazy, flag_equal;
  int st, sz;
  T (*addition_fun)(T, T);
  T invalid_value;
  segtree_t() {}
  segtree_t(int start, int finish, T* arr, T (*add_fun)(T, T), T invalid_val) {
    int size = (finish + 1) * 2;
    int tree_size = 2;
    while (tree_size < size) tree_size *= 2;
    t = vector<T>(tree_size);
    lazy = vector<T>(tree_size);
    flag_equal = vector<T>(tree_size);
    st = start;
    sz = finish;
    addition_fun = add_fun;
    invalid_value = invalid_val;
    build(1, start, finish, arr);
  }
  void build(int i, int l, int r, T* arr) {
    if (l > r) return;
    lazy[i] = 0;
    flag_equal[i] = 0;
    if (l == r) {
      t[i] = arr[l];
    } else {
      build(i * 2, l, (l + r) / 2, arr);
      build(i * 2 + 1, (l + r) / 2 + 1, r, arr);
      t[i] = addition_fun(t[i * 2], t[i * 2 + 1]);
    }
  }
  void inc_range(int l, int r, T value) {
    if (l > r) return;
    inc_range_rec(1, st, sz, l, r, value);
  }
  void set_values(int l, int r, T value) {
    set_values_rec(1, st, sz, l, r, value);
  }
  void inc_range_rec(int i, int l, int r, int tl, int tr, T value) {
    if (lazy[i] != 0) {
      t[i] += lazy[i];
      if (l != r) {
        lazy[i * 2] += lazy[i];
        lazy[i * 2 + 1] += lazy[i];
      }
      lazy[i] = 0;
    }
    if (r < tl or l > tr) return;
    if (l > r) return;
    if (l >= tl and r <= tr) {
      if (l != r) {
        lazy[i * 2] += value;
        lazy[i * 2 + 1] += value;
      }
      t[i] += value;
    } else {
      inc_range_rec(i * 2, l, (l + r) / 2, tl, tr, value);
      inc_range_rec(i * 2 + 1, (l + r) / 2 + 1, r, tl, tr, value);
      t[i] = addition_fun(t[i * 2], t[i * 2 + 1]);
    }
  }
  T query_rec(int i, int l, int r, int tl, int tr) {
    if (flag_equal[i] != 0) {
      if (l != r) {
        t[i * 2] = t[i];
        t[i * 2 + 1] = t[i];
        flag_equal[i * 2] = 1;
        flag_equal[i * 2 + 1] = 1;
      }
      flag_equal[i] = 0;
    }
    if (r < tl or l > tr) return invalid_value;
    if (l > r) return invalid_value;
    if (lazy[i] != 0) {
      t[i] += lazy[i];
      if (l != r) {
        lazy[i * 2] += lazy[i];
        lazy[i * 2 + 1] += lazy[i];
      }
      lazy[i] = 0;
    }
    if (l >= tl and r <= tr) {
      return t[i];
    } else {
      T m1 = query_rec(i * 2, l, (l + r) / 2, tl, tr);
      T m2 = query_rec(i * 2 + 1, (l + r) / 2 + 1, r, tl, tr);
      if (m1 == invalid_value && m2 == invalid_value) return invalid_value;
      if (m1 == invalid_value) return m2;
      if (m2 == invalid_value) return m1;
      return addition_fun(m1, m2);
    }
  }
  T query(int l, int r) { return query_rec(1, st, sz, l, r); }
  void set_values_rec(int i, int l, int r, int tl, int tr, T value) {
    if (flag_equal[i] != 0) {
      if (l != r) {
        t[i * 2] = t[i];
        t[i * 2 + 1] = t[i];
        flag_equal[i * 2] = 1;
        flag_equal[i * 2 + 1] = 1;
      }
      flag_equal[i] = 0;
    }
    if (r < tl || l > tr) return;
    if (l > r) return;
    if (l >= tl and r <= tr) {
      t[i] = value;
      flag_equal[i] = 1;
    } else {
      set_values_rec(i * 2, l, (l + r) / 2, tl, tr, value);
      set_values_rec(i * 2 + 1, (l + r) / 2 + 1, r, tl, tr, value);
      t[i] = addition_fun(t[i * 2], t[i * 2 + 1]);
    }
  }
  ~segtree_t() {}
};
const int maxn = 1e5 + 5;
const int maxm = 1e5 + 5;
const int maxk = 1e5 + 5;
const int maxq = 1e5 + 5;
int n, m;
mt19937 mt(time(0));
int table[maxn];
set<int> candidates;
bool is_good(int value, int i) {
  if (i - 1 > 0 && table[i - 1] == value) return false;
  if (i - m > 0 && table[i - m] == value) return false;
  return true;
}
int try_random(int i) {
  int chance = mt() % (n * m);
  set<int>::iterator it = candidates.upper_bound(chance);
  if (it == candidates.end()) advance(it, -1);
  int value = (*it);
  int adj1 = value - 1;
  int adj2 = value + 1;
  int adj3 = value - m;
  int adj4 = value + m;
  if ((value - 1) % m == 0 || is_good(adj1, i)) {
    if ((value - 1) % m == (m - 1) || is_good(adj2, i)) {
      if (is_good(adj3, i)) {
        if (is_good(adj4, i)) return value;
      }
    }
  }
  return 0;
}
int main() {
  cin >> n >> m;
  int done = 0;
  for (int global_try = 0; global_try <= 1000; global_try++) {
    int success = 1;
    for (int i = 1; i <= n * m; i++) candidates.insert(i);
    for (int i = 1; i <= n * m; i++) {
      bool good = 0;
      for (int my_try = 0; my_try < 10; my_try++) {
        int val = try_random(i);
        if (val != 0) {
          table[i] = val;
          candidates.erase(val);
          good = 1;
          break;
        }
      }
      if (!good) {
        success = 0;
        break;
      }
    }
    if (success) {
      done = 1;
      break;
    }
  }
  if (done) {
    cout << "YES\n";
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        cout << table[i * m + j + 1] << " ";
      }
      cout << '\n';
    }
  } else {
    cout << "NO\n";
  }
}

### Prompt

Please formulate a Cpp solution to the following problem:

Students went into a class to write a test and sat in some way. The teacher thought: "Probably they sat in this order to copy works of each other. I need to rearrange them in such a way that students that were neighbors are not neighbors in a new seating."

The class can be represented as a matrix with n rows and m columns with a student in each cell. Two students are neighbors if cells in which they sit have a common side.

Let's enumerate students from 1 to n·m in order of rows. So a student who initially sits in the cell in row i and column j has a number (i - 1)·m + j. You have to find a matrix with n rows and m columns in which all numbers from 1 to n·m appear exactly once and adjacent numbers in the original matrix are not adjacent in it, or determine that there is no such matrix.

Input

The only line contains two integers n and m (1 ≤ n, m ≤ 105; n·m ≤ 105) — the number of rows and the number of columns in the required matrix.

Output

If there is no such matrix, output "NO" (without quotes). 

Otherwise in the first line output "YES" (without quotes), and in the next n lines output m integers which form the required matrix.

Examples

Input

2 4


Output

YES
5 4 7 2 
3 6 1 8 


Input

2 1


Output

NO

Note

In the first test case the matrix initially looks like this:
    
    
      
    1 2 3 4  
    5 6 7 8  
    

It's easy to see that there are no two students that are adjacent in both matrices.

In the second test case there are only two possible seatings and in both of them students with numbers 1 and 2 are neighbors.

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
const long double EPS = 1e-10;
const long long MOD = 1e9 + 7;
const long double PI = 3.1415926535897932384626433832795028841;
long long powmod(long long a, long long b) {
  long long res = 1;
  a %= MOD;
  for (; b; b >>= 1) {
    if (b & 1) res = res * a % MOD;
    a = a * a % MOD;
  }
  return res;
}
ostream& operator<<(std::ostream& stream, const long long* arr) {
  int i = 0;
  cout << "{";
  while (arr[i] != INT_MAX) {
    cout << arr[i];
    if (arr[i + 1] != INT_MAX) cout << ",";
    i++;
  }
  cout << "}";
  return stream;
}
ostream& operator<<(std::ostream& stream, const vector<int> vec) {
  cout << "{";
  for (int i = 0; i < vec.size(); i++) {
    cout << vec[i];
    if (i != vec.size() - 1) cout << ",";
  }
  cout << "}";
  return stream;
}
ostream& operator<<(std::ostream& stream,
                    const pair<long long, long long>& vec) {
  cout << "(" << vec.first << ',' << vec.second << ")";
  return stream;
}
template <class T>
struct segtree_t {
  vector<T> t, lazy, flag_equal;
  int st, sz;
  T (*addition_fun)(T, T);
  T invalid_value;
  segtree_t() {}
  segtree_t(int start, int finish, T* arr, T (*add_fun)(T, T), T invalid_val) {
    int size = (finish + 1) * 2;
    int tree_size = 2;
    while (tree_size < size) tree_size *= 2;
    t = vector<T>(tree_size);
    lazy = vector<T>(tree_size);
    flag_equal = vector<T>(tree_size);
    st = start;
    sz = finish;
    addition_fun = add_fun;
    invalid_value = invalid_val;
    build(1, start, finish, arr);
  }
  void build(int i, int l, int r, T* arr) {
    if (l > r) return;
    lazy[i] = 0;
    flag_equal[i] = 0;
    if (l == r) {
      t[i] = arr[l];
    } else {
      build(i * 2, l, (l + r) / 2, arr);
      build(i * 2 + 1, (l + r) / 2 + 1, r, arr);
      t[i] = addition_fun(t[i * 2], t[i * 2 + 1]);
    }
  }
  void inc_range(int l, int r, T value) {
    if (l > r) return;
    inc_range_rec(1, st, sz, l, r, value);
  }
  void set_values(int l, int r, T value) {
    set_values_rec(1, st, sz, l, r, value);
  }
  void inc_range_rec(int i, int l, int r, int tl, int tr, T value) {
    if (lazy[i] != 0) {
      t[i] += lazy[i];
      if (l != r) {
        lazy[i * 2] += lazy[i];
        lazy[i * 2 + 1] += lazy[i];
      }
      lazy[i] = 0;
    }
    if (r < tl or l > tr) return;
    if (l > r) return;
    if (l >= tl and r <= tr) {
      if (l != r) {
        lazy[i * 2] += value;
        lazy[i * 2 + 1] += value;
      }
      t[i] += value;
    } else {
      inc_range_rec(i * 2, l, (l + r) / 2, tl, tr, value);
      inc_range_rec(i * 2 + 1, (l + r) / 2 + 1, r, tl, tr, value);
      t[i] = addition_fun(t[i * 2], t[i * 2 + 1]);
    }
  }
  T query_rec(int i, int l, int r, int tl, int tr) {
    if (flag_equal[i] != 0) {
      if (l != r) {
        t[i * 2] = t[i];
        t[i * 2 + 1] = t[i];
        flag_equal[i * 2] = 1;
        flag_equal[i * 2 + 1] = 1;
      }
      flag_equal[i] = 0;
    }
    if (r < tl or l > tr) return invalid_value;
    if (l > r) return invalid_value;
    if (lazy[i] != 0) {
      t[i] += lazy[i];
      if (l != r) {
        lazy[i * 2] += lazy[i];
        lazy[i * 2 + 1] += lazy[i];
      }
      lazy[i] = 0;
    }
    if (l >= tl and r <= tr) {
      return t[i];
    } else {
      T m1 = query_rec(i * 2, l, (l + r) / 2, tl, tr);
      T m2 = query_rec(i * 2 + 1, (l + r) / 2 + 1, r, tl, tr);
      if (m1 == invalid_value && m2 == invalid_value) return invalid_value;
      if (m1 == invalid_value) return m2;
      if (m2 == invalid_value) return m1;
      return addition_fun(m1, m2);
    }
  }
  T query(int l, int r) { return query_rec(1, st, sz, l, r); }
  void set_values_rec(int i, int l, int r, int tl, int tr, T value) {
    if (flag_equal[i] != 0) {
      if (l != r) {
        t[i * 2] = t[i];
        t[i * 2 + 1] = t[i];
        flag_equal[i * 2] = 1;
        flag_equal[i * 2 + 1] = 1;
      }
      flag_equal[i] = 0;
    }
    if (r < tl || l > tr) return;
    if (l > r) return;
    if (l >= tl and r <= tr) {
      t[i] = value;
      flag_equal[i] = 1;
    } else {
      set_values_rec(i * 2, l, (l + r) / 2, tl, tr, value);
      set_values_rec(i * 2 + 1, (l + r) / 2 + 1, r, tl, tr, value);
      t[i] = addition_fun(t[i * 2], t[i * 2 + 1]);
    }
  }
  ~segtree_t() {}
};
const int maxn = 1e5 + 5;
const int maxm = 1e5 + 5;
const int maxk = 1e5 + 5;
const int maxq = 1e5 + 5;
int n, m;
mt19937 mt(time(0));
int table[maxn];
set<int> candidates;
bool is_good(int value, int i) {
  if (i - 1 > 0 && table[i - 1] == value) return false;
  if (i - m > 0 && table[i - m] == value) return false;
  return true;
}
int try_random(int i) {
  int chance = mt() % (n * m);
  set<int>::iterator it = candidates.upper_bound(chance);
  if (it == candidates.end()) advance(it, -1);
  int value = (*it);
  int adj1 = value - 1;
  int adj2 = value + 1;
  int adj3 = value - m;
  int adj4 = value + m;
  if ((value - 1) % m == 0 || is_good(adj1, i)) {
    if ((value - 1) % m == (m - 1) || is_good(adj2, i)) {
      if (is_good(adj3, i)) {
        if (is_good(adj4, i)) return value;
      }
    }
  }
  return 0;
}
int main() {
  cin >> n >> m;
  int done = 0;
  for (int global_try = 0; global_try <= 1000; global_try++) {
    int success = 1;
    for (int i = 1; i <= n * m; i++) candidates.insert(i);
    for (int i = 1; i <= n * m; i++) {
      bool good = 0;
      for (int my_try = 0; my_try < 10; my_try++) {
        int val = try_random(i);
        if (val != 0) {
          table[i] = val;
          candidates.erase(val);
          good = 1;
          break;
        }
      }
      if (!good) {
        success = 0;
        break;
      }
    }
    if (success) {
      done = 1;
      break;
    }
  }
  if (done) {
    cout << "YES\n";
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        cout << table[i * m + j + 1] << " ";
      }
      cout << '\n';
    }
  } else {
    cout << "NO\n";
  }
}

```