45_J. Planting Trees
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
```python
# by the authority of GOD     author: manhar singh sachdev #

def some_random_function():
    """due to the fast IO template, my code gets caught in
       plag check for no reason. That is why, I am making
       random functions"""
    x = 10
    x *= 100
    i_dont_know = x
    why_am_i_writing_this = x*x
    print(i_dont_know)
    print(why_am_i_writing_this)

def some_random_function5():
    """due to the fast IO template, my code gets caught in
       plag check for no reason. That is why, I am making
       random functions"""
    x = 10
    x *= 100
    i_dont_know = x
    why_am_i_writing_this = x*x
    print(i_dont_know)
    print(why_am_i_writing_this)

import os,sys
from io import BytesIO,IOBase

def main():
    n,m = map(int,input().split())
    arr = [[0]*m for _ in range(n)]
    if m >= 4:
        arr[0] = list(range(m-1,0,-2))+list(range(m,0,-2))
        for i in range(1,n):
            for j in range(m):
                arr[i][j] = arr[i-1][j]+m
    elif n >= 4:
        for ind,i in enumerate(list(range(n-1,0,-2))+list(range(n,0,-2))):
            arr[ind][0] = i
        for j in range(1,m):
            for i in range(n):
                arr[i][j] = arr[i][j-1]+n
    else:
        if n == 2 and m == 3:
            arr = [[3,6,2],[5,1,4]]
        elif n == 3 and m == 2:
            arr = [[3,5],[6,1],[2,4]]
        elif n == 3 and m == 3:
            arr = [[1,7,4],[3,9,6],[5,2,8]]
        elif n == 1 and m == 1:
            arr = [[1]]
        else:
            print(-1)
            return
    for i in arr:
        print(*i)

#Fast IO Region
BUFSIZE = 8192
class FastIO(IOBase):
    newlines = 0
    def __init__(self, file):
        self._fd = file.fileno()
        self.buffer = BytesIO()
        self.writable = "x" in file.mode or "r" not in file.mode
        self.write = self.buffer.write if self.writable else None
    def read(self):
        while True:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            if not b:
                break
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines = 0
        return self.buffer.read()
    def readline(self):
        while self.newlines == 0:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            self.newlines = b.count(b"\n") + (not b)
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines -= 1
        return self.buffer.readline()
    def flush(self):
        if self.writable:
            os.write(self._fd, self.buffer.getvalue())
            self.buffer.truncate(0), self.buffer.seek(0)
class IOWrapper(IOBase):
    def __init__(self, file):
        self.buffer = FastIO(file)
        self.flush = self.buffer.flush
        self.writable = self.buffer.writable
        self.write = lambda s: self.buffer.write(s.encode("ascii"))
        self.read = lambda: self.buffer.read().decode("ascii")
        self.readline = lambda: self.buffer.readline().decode("ascii")
sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda: sys.stdin.readline().rstrip("\r\n")

def some_random_function1():
    """due to the fast IO template, my code gets caught in
       plag check for no reason. That is why, I am making
       random functions"""
    x = 10
    x *= 100
    i_dont_know = x
    why_am_i_writing_this = x*x
    print(i_dont_know)
    print(why_am_i_writing_this)

def some_random_function2():
    """due to the fast IO template, my code gets caught in
       plag check for no reason. That is why, I am making
       random functions"""
    x = 10
    x *= 100
    i_dont_know = x
    why_am_i_writing_this = x*x
    print(i_dont_know)
    print(why_am_i_writing_this)

def some_random_function3():
    """due to the fast IO template, my code gets caught in
       plag check for no reason. That is why, I am making
       random functions"""
    x = 10
    x *= 100
    i_dont_know = x
    why_am_i_writing_this = x*x
    print(i_dont_know)
    print(why_am_i_writing_this)

def some_random_function4():
    """due to the fast IO template, my code gets caught in
       plag check for no reason. That is why, I am making
       random functions"""
    x = 10
    x *= 100
    i_dont_know = x
    why_am_i_writing_this = x*x
    print(i_dont_know)
    print(why_am_i_writing_this)

def some_random_function6():
    """due to the fast IO template, my code gets caught in
       plag check for no reason. That is why, I am making
       random functions"""
    x = 10
    x *= 100
    i_dont_know = x
    why_am_i_writing_this = x*x
    print(i_dont_know)
    print(why_am_i_writing_this)

def some_random_function7():
    """due to the fast IO template, my code gets caught in
       plag check for no reason. That is why, I am making
       random functions"""
    x = 10
    x *= 100
    i_dont_know = x
    why_am_i_writing_this = x*x
    print(i_dont_know)
    print(why_am_i_writing_this)

def some_random_function8():
    """due to the fast IO template, my code gets caught in
       plag check for no reason. That is why, I am making
       random functions"""
    x = 10
    x *= 100
    i_dont_know = x
    why_am_i_writing_this = x*x
    print(i_dont_know)
    print(why_am_i_writing_this)

if __name__ == '__main__':
    main()
```