Problem:
 Score : 100 points    Problem Statement Having learned the multiplication table, Takahashi can multiply two integers between 1 and 9 (inclusive) together. He cannot do any other calculation.  Given are two integers A and B .  If Takahashi can calculate A \times B , print the result; if he cannot, print -1 instead.      Constraints  1 \leq A \leq 20  1 \leq B \leq 20  All values in input are integers.         Input Input is given from Standard Input in the following format:  A  B       Output If Takahashi can calculate A \times B , print the result; if he cannot, print -1 .        Sample Input 1 2 5      Sample Output 1 10  2 \times 5 = 10 .       Sample Input 2 5 10      Sample Output 2 -1  5\times 10 = 50 , but Takahashi cannot do this calculation, so print -1 instead.       Sample Input 3 9 9      Sample Output 3 81

Solution (Python):

from __future__ import division, print_function

import os
import sys
from io import BytesIO, IOBase

if sys.version_info[0] < 3:
    from __builtin__ import xrange as range
    from future_builtins import ascii, filter, hex, map, oct, zip


def main():
    a, b = map(int, input().split())

    if a < 10 and b < 10:
        print(a * b)
    else:
        print(-1)




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")


def print(*args, **kwargs):
    """Prints the values to a stream, or to sys.stdout by default."""
    sep, file = kwargs.pop("sep", " "), kwargs.pop("file", sys.stdout)
    at_start = True
    for x in args:
        if not at_start:
            file.write(sep)
        file.write(str(x))
        at_start = False
    file.write(kwargs.pop("end", "\n"))
    if kwargs.pop("flush", False):
        file.flush()


if sys.version_info[0] < 3:
    sys.stdin, sys.stdout = FastIO(sys.stdin), FastIO(sys.stdout)
else:
    sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)

input = lambda: sys.stdin.readline().rstrip("\r\n")



if __name__ == "__main__":
    main()

Solution (Python):
A,B = map(int,input().split())
if A <= 9 and B <= 9:
    print(A*B)
else:
    print(-1)

Solution (Python):
A, B = map(int, input().split())
if A < 10 and B < 10:
    print(A*B)
else:
    print(-1)

Solution (Python):
if __name__ == '__main__':
    A, B = map(int, input().split())
    if A < 10 and B < 10:
        print(A*B)
    else:
        print(-1)

Solution (Python):
a, b = map(int, input().split())
if a >= 10 or b >= 10:
    print(-1)
else:
    print(a * b)

Solution (Python):
import sys
read = sys.stdin.buffer.read
input = sys.stdin.buffer.readline
inputs= sys.stdin.buffer.readlines























def main():
	a,b=map(int,input().split())
	if a<=9 and b<=9:
		print(a*b)
	else:
		print(-1)
	




if __name__ == '__main__':
	main()

Solution (Python):
a,b = map(int, input().split())

if a > 9 or b > 9:
    print(-1)
else:
    print(a*b)

Solution (Python):
def test():
    a,b = map(int,input().split())
    if a >= 10 or b >= 10:
        print("-1")
    else:
        print(a*b)


if __name__ == "__main__":
    test()

Solution (Python):
A,B = map(int,input().split())
ans = -1
if A < 10 and B < 10:
    ans = A*B
print(ans)

Solution (Python):
a,b = map(int, input().split())
if a >= 10 or b >= 10:
    print("-1")
else:
    print(a*b)

Solution (Python):
A, B = map(int, input().split())


if A > 9 or B > 9:
    print(-1)
else:
    print(A*B)

Solution (Python):

import bisect
import heapq
import math
import random
import sys
from collections import Counter, defaultdict, deque
from decimal import ROUND_CEILING, ROUND_HALF_UP, Decimal
from functools import lru_cache, reduce
from itertools import combinations, combinations_with_replacement, product, permutations
from operator import add, mul, sub

sys.setrecursionlimit(100000)
input = sys.stdin.readline
INF = 2**62-1

def read_int():
    return int(input())


def read_int_n():
    return list(map(int, input().split()))


def read_float():
    return float(input())


def read_float_n():
    return list(map(float, input().split()))


def read_str():
    return input().strip()


def read_str_n():
    return list(map(str, input().split()))


def error_print(*args):
    print(*args, file=sys.stderr)


def mt(f):
    import time

    def wrap(*args, **kwargs):
        s = time.time()
        ret = f(*args, **kwargs)
        e = time.time()

        error_print(e - s, 'sec')
        return ret

    return wrap


@mt
def slv(A, B):
    if 1 <= A <= 9 and 1 <= B <= 9:
        return A * B
    return -1

def main():
    A, B = read_int_n()
    print(slv(A, B))


if __name__ == '__main__':
    main()

Solution (Python):

import sys
input = sys.stdin.readline


def main():
    a, b = map(int, input().split())
    if a > 9 or b > 9:
        print(-1)
    else:
        print(a*b)


if __name__ == '__main__':
    main()

Solution (Python):
a, b = map(int, input().split())
if a >= 1 and a <= 9 and b >= 1 and b <= 9:
    print(a * b)
else:
    print(-1)

Solution (Python):
a,b=map(int,input().split())
if a<10 and b<10:
    print(a*b)
else:
    print(-1)

Solution (Python):
A,B = map(int,input().split())

if A <= 9 and B <= 9:
    print(A*B)
else:
    print(-1)

Solution (Python):
A, B = map(int, input().split())
if A >= 10 or B >= 10:
    print(-1)
else:
    print(A*B)

Solution (Python):
import sys
a, b = [int(i) for i in sys.stdin.readline().split()]
if a > 9 or a <= 0 or b > 9 or b <= 0:
    print(-1)
else:
    print(a * b)

Solution (Python):
a, b = map(int, input().split())

if a >= 10 or b >= 10:
    print(-1) 
else:
    print(a*b)

Solution (Python):
a, b = map(int, input().split())

if a < 10 and b < 10:
    print(a * b)
else:
    print(-1)

Solution (Python):
A, B = map(int, input().split())

if A < 10 and B < 10:
    print(A*B)
else:
    print(-1)

Solution (Python):
A,B=map(int,input().split())
print(A*B if A<=9 and B<=9 else -1)

Solution (Python):
A, B = map(int, input().split())
if A > 0 and A < 10 and B > 0 and B < 10:
  print(A*B)
else:
  print(-1)

Solution (Python):
a, b = map(int, input().split())
print(a * b if max(a, b) < 10 else -1)

Solution (Python):
A,B = map(int, input().split())
result = A*B

if A > 9 or B > 9:
    print('-1')
else:
    print(result)

Solution (Python):
import sys
input = sys.stdin.readline
sys.setrecursionlimit(10 ** 7)


def main():
    a, b = map(int, input().split())
    if a <= 9 and b <= 9:
        print(a*b)
    else:
        print(-1)


if __name__ == '__main__':
    main()

Solution (Python):
def main():
    a, b = map(int, input().split())
    if 1 <= a and a <= 9 and 1 <= b and b <= 9:
        print(a * b)
    else:
        print(-1)


if __name__ == '__main__':
    main()

Solution (Python):
A, B = map(int, input().split())
if A <= 9 and B <= 9:
    print(A * B)
else:
    print(-1)

Solution (Python):
A, B = list(map(int, input().split()))
if A >= 10 or B >= 10:
    print(-1)
else:
    print(A*B)

Solution (Python):
A, B = map(int, input().split())
print(A * B if A <= 9 and B <= 9 else -1)

Solution (Python):
if __name__ == '__main__':
    x, y = map(int, input().split())
    if(x > 9 or y > 9):
        print("-1")
    else:
        print(x*y)

Solution (Python):
a,b = map(int,input().split())
print(a*b) if max(a,b)<10 else print(-1)

Solution (Python):
if __name__ == "__main__":
    A, B = map(int, input().split())

    if A > 9 or B > 9:
        print(-1)
    else:
        print(A*B)

Solution (Python):
A,B = map(int,input().split())

if A <= 9 and B <= 9:
    print(A*B)
else:
    print(-1)

Solution (Python):
a,b = map(int,input().split())
if a >= 10 or b >= 10:
  print(-1)
else:
  print(a*b)

Solution (Python):
a, b = map(int, input().split())

if 1 <= a <= 9 and 1 <= b <= 9:
    print(a*b)
else:
    print(-1)

Solution (Python):
a,b=map(int,input().split())
if 1<=a<=9 and 1<=b<=9:
  print(a*b)
else:
  print(-1)

Solution (Python):
A, B = map(int, input().split())
if A > 9 or B > 9 or A < 0 or B < 0:
  print(-1)
else:
  print(A*B)

Solution (Python):
a, b = map(int, input().split())

if a > 9 or b > 9:
    ans = -1
else:
    ans = a*b

print(ans)

Solution (Python):
x,y = map(int,input().split())
if x < 1 or x > 9 or y < 1 or y > 9:
    print(-1)
else:
    print(x * y)

Solution (Python):


A, B = map(int, input().split())
if A <= 9 and B <= 9:
    print(A * B)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())

if ((a < 10) and (b<10)):
    print(a*b)
else:
    print(-1)

Solution (Python):
a,b=map(int,input().split())

if max(a,b)>9:
    print(-1)
else:
    print(a*b)

Solution (Python):
n,m = map(int,input().split())
if 1<=n<=9 and 1<=m<=9:
    print(n*m)
else:
    print(-1)

Solution (Python):


A, B = [int(x) for x in input().split(" ")]

if 1 <= A <= 9 and 1 <= B <= 9:
    print(A * B)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())
if a < 10 and b < 10:
    print(a * b)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())
if a > 9 or b > 9:
    print(-1)
else:
    print(a * b)

Solution (Python):
A,B = map(int,input().split())
if((A>=10)or(B>=10)): print(-1)
else: print(A*B)

Solution (Python):
a,b=map(int,input().split())
if a >= 10 or b >= 10:
    print("-1")
else:
    print(a*b)

Solution (Python):
a,b=map(int,input().split())
if a<10 and b<10:
  print(a*b)
else:
  print(-1)

Solution (Python):

N, M=(int(i) for i in input().split())

if N<=9:
    if M<=9:
        print(N*M)
    else:
        print(-1)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())
if a < 10 and b < 10:
    print(a * b)
else:
    print(-1)

Solution (Python):
a,b = (int(i) for i in input().split())
if a < 10 and b < 10: print(a*b)
else: print(-1)

Solution (Python):
import sys

sys.setrecursionlimit(10**7)
A, B = map(int, input().split())

if A < 10 and B < 10:
    print(A*B)
else:
    print(-1)

Solution (Python):
A, B = map(int, input().split())
if 1 <= A <= 9 and 1 <= B <= 9:
    print(A*B)
else:
    print(-1)

Solution (Python):
a,b=map(int,input().split())
if a<=9 and b<=9:
    print(a*b)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())
if a < 10 and b < 10:
    print(a * b)
else:
    print(-1)

Solution (Python):
a,b = map(int,input().split())
if a>=10 or b>=10:
    print(-1)
else:
    print(a*b)

Solution (Python):
A, B = map(int, input().split())

if A < 10 and B < 10:
    print(A * B)
else:
    print(-1)

Solution (Python):
a,b = map(int,input().split())
if a <= 9 and b <= 9 and a >= 1 and b >= 1:
    print(a*b)
else:
    print(-1)

Solution (Python):
a, b = [int(i) for i in input().split()]
if a <= 9 and b <= 9:
    print(a*b)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())

if not(a<=9) or not(b<=9):
    print(-1)
else:
    print(a*b)

Solution (Python):
a, b = map(int, input().split())
if a < 10 and b < 10:
    print(a*b)
else:
    print(-1)

Solution (Python):
a,b=map(int,input().split())
if(a > 9 or b > 9):
    print(-1)
else:
    print(a*b)

Solution (Python):
A,B = list(map(int,input().split()))

if A<=9 and A>=1 and B<=9 and B>=1:
    print(A*B)
else:
    print(-1)

Solution (Python):
A, B = map(int, input().split())
if A >= 10 or B >= 10:
    print(-1)
else:
    print(A * B)

Solution (Python):
A,B = map(int,input().split())
if A< 10 and B <10:
  print(A*B)
else:
  print(-1)

Solution (Python):
a,b = map(int,input().split())

if a <= 9 and b <= 9:
    print(a*b)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())

if 1 <= a <= 9 and 1 <= b <= 9:
    print(a * b)
else:
    print(-1)

Solution (Python):
a,b= map(int, input().split())
if a<=9 and b<=9:
    print(a*b)
else:
    print(-1)

Solution (Python):
import sys
import math
input = sys.stdin.readline

A, B = (int(i) for i in input().split())


if A > 9 or B > 9:
    print("-1")
else:
    print(A*B)

Solution (Python):
a,b=map(int,input().split())
if a>=10 or b>=10:
  print(-1)
else:
  print(a*b)

Solution (Python):
a, b = map(int, input().split())
if a >= 10 or b >= 10: print(-1)
else: print(a * b)

Solution (Python):
n,m = map(int,input().split())
if n < 10 and m < 10:
    print(n*m)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())

if a < 10 and b < 10:
    print(a*b)
else:
    print(-1)

Solution (Python):
A, B = map(int, input().split())

if A <= 9 and B <= 9:
    print(A*B)
else:
    print(-1)

Solution (Python):
a,b=map(int,input().split())

if 1<=a<=9 and 1<=b<=9:
  print(a*b)
else:
  print(-1)

Solution (Python):

from fractions import gcd

from math import factorial as f

from math import ceil,floor,sqrt

from sys import exit

from copy import deepcopy
import numpy as np

import bisect
import re


ii = lambda : int(input())
mi = lambda : map(int,input().split())
li = lambda : list(map(int,input().split()))



def main():
    a,b = mi()
    if a>9 or b > 9:
        print(-1)
    else:
        print(a*b)


main()

Solution (Python):
a,b = map(int, input().split())
if a>9 or b>9:
    print(-1)
else:
    print(a*b)

Solution (Python):
A,B = map(int,input().split())
print(A*B if 1<=A<=9 and 1<=B<=9 else -1)

Solution (Python):

from collections import defaultdict,deque
import sys,heapq,bisect,math,itertools,string,queue,copy,time
sys.setrecursionlimit(10**8)
INF = float('inf')
mod = 10**9+7
eps = 10**-7
def inp(): return int(sys.stdin.readline())
def inpl(): return list(map(int, sys.stdin.readline().split()))
def inpl_str(): return list(sys.stdin.readline().split())

A,B = inpl()
if A <= 9 and B <= 9:
    print(A*B)
else:
    print(-1)

Solution (Python):
A, B = map(int,input().split())
if A < 10 and B < 10:
    print(A*B)
else:
    print(-1)

Solution (Python):
a,b=map(int,input().split())
if a>9 or b>9:
  print("-1")
else:
  print(a*b)

Solution (Python):
a, b = map(int, input().split())
print(a*b if a < 10 and b < 10 else -1)

Solution (Python):
A, B = map(int, input().strip().split())

if A <= 9 and B <= 9:
	print(A * B)
else:
	print(-1)

Solution (Python):
a,b=map(int,input().split())
if(a<10 and b<10):
    print(a*b)
else:
    print(-1)

Solution (Python):
inpl = lambda: list(map(int,input().split()))
A, B = inpl()
if A <= 9 and B <= 9:
    print(A*B)
else:
    print(-1)

Solution (Python):

from __future__ import division, print_function
from collections import defaultdict, Counter, deque
from future_builtins import ascii, filter, hex, map, oct, zip
from random import randint
from itertools import imap as map, izip as zip, permutations, combinations, combinations_with_replacement
from __builtin__ import xrange as range
from math import ceil
from _continuation import continulet
from cStringIO import StringIO
from io import IOBase
import __pypy__
from bisect import bisect, insort, bisect_left, bisect_right
import sys
import os
import re
sys.setrecursionlimit(9999)
inf = float('inf')
mod = int(1e9) + 7
mod_ = 998244353
N = 5001
 
'''
Check for special cases (n=1)
One wrong submission = 10 mins penalty!
do smth instead of nothing and stay organized
'''

def main():
	a, b = map(int, input().split())
	if max(a, b) <= 9:
		print(a*b)
	else:
		print(-1)


BUFSIZE = 8192
class FastI(IOBase):
	def __init__(self, file):
		self._fd = file.fileno()
		self._buffer = StringIO()
		self.newlines = 0
 
	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("\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()
class FastO(IOBase):
	def __init__(self, file):
		self._fd = file.fileno()
		self._buffer = __pypy__.builders.StringBuilder()
		self.write = lambda s: self._buffer.append(s)
 
	def flush(self):
		os.write(self._fd, self._buffer.build())
		self._buffer = __pypy__.builders.StringBuilder()
def print(*args, **kwargs):
	sep, file = kwargs.pop("sep", " "), kwargs.pop("file", sys.stdout)
	at_start = True
	for x in args:
		if not at_start:
			file.write(sep)
		file.write(str(x))
		at_start = False
	file.write(kwargs.pop("end", "\n"))
	if kwargs.pop("flush", False):
		file.flush()
def gcd(x, y):
	while y:
		x, y = y, x % y
	return x
sys.stdin, sys.stdout = FastI(sys.stdin), FastO(sys.stdout)
def input(): return sys.stdin.readline().rstrip("\r\n")
if __name__ == "__main__":
	def bootstrap(cont):
		call, arg = cont.switch()
		while True:
			call, arg = cont.switch(to=continulet(
				lambda _, f, args: f(*args), call, arg))
	cont = continulet(bootstrap)
	cont.switch()
	main()

Solution (Python):
from sys import stdin
a, b = map(int, stdin.readline().rstrip().split())
if a <= 9 and b <= 9:
    print(a*b)
else:
    print(-1)

Solution (Python):
import sys

input = sys.stdin.readline

A, B = list(map(int,input().split()))

if A>=10 or B>=10:
	ans = -1
else:
	ans = A*B

print(ans)

Solution (Python):
b, c = map(int, input().split())
if b < 10 and c < 10:
    print(b*c)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())

if a > 9 or b > 9:
    print(-1);
else:
    print(a * b)

Solution (Python):
n, m = map(int, input().split())
if n < 10 and m < 10:
  print(n * m)
else: print(-1)

Solution (Python):
def nums():
    return list(map(int,input().split(" ")))
def num():
    return int(input())


a,b = nums()
if a <= 9 and b <= 9:
    print(a * b)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())
if a < 10 and b < 10:
    print(a*b)
else:
    print(-1)

Solution (Python):
A, B = map(int, input().split())
if 0 < A < 10 and 0 < B < 10:
    print(A* B)
else:
    print(-1)

Solution (Python):
a,b=map(int,input().split())
if 0<a<10 and 0<b<10:
    print(a*b)
else:
    print('-1')

Solution (Python):
def main():
    a, b = map(int, input().split())
    if a > 9 or b > 9:
        print(str(-1))
    else:
        print(a*b)


if __name__ == '__main__':
    main()

Solution (Python):
def two_int():
    N, K = map(int, input().split())
    return N,K

def one_int():
    return int(input())

def one_str():
    return input()

def many_int():
    return list(map(int, input().split()))

A,B=two_int()
if A>9 or B>9:
    print(-1)
else:
    print(A*B)

Solution (Python):
a,b=map(int,input().split())
if a<10 and b<10:
    print(a*b)
else:
    print(-1)

Solution (Python):
A,B = (int(x) for x in input().split())

if A >= 10 or B >= 10:
    print(-1)
else:
    print(A*B)

Solution (Python):



A, B = list(map(int, input().split(" ")))

if 0 < A and A < 10 and 0 < B and B < 10:
    print(A * B)
else:
    print(-1)

Solution (Python):
def main():
    a,b=map(int,input().split())
    if a<10 and b<10:
        print(a*b)
    else:
        print(-1)
    
main()

Solution (Python):
A, B = map(int, input().split())

if 1<=A<=9 and 1<=B<=9:
  print(A*B)
else:
  print(-1)

Solution (Python):
a,b = map(int,input().split())
if a > 9 or b > 9:
    print(-1)
else:
    print(a*b)

Solution (Python):
a, b = map(int, input().split())

if a > 9 or b > 9:
    print(-1)
else:
    print(a*b)

Solution (Python):
import math,string,itertools,fractions,heapq,collections,re,array,bisect,sys,random,time,queue,copy

sys.setrecursionlimit(10**7)
inf=10**20
mod=10**9+7
dd=[(-1,0),(0,1),(1,0),(0,-1)]
ddn=[(-1,0),(-1,1),(0,1),(1,1),(1,0),(1,-1),(0,-1),(-1,-1)]

def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def I(): return int(sys.stdin.readline())
def LS(): return sys.stdin.readline().split()
def S(): return input()

def main():
  a,b=LI()
  if a>9:
    return -1
  if b>9:
    return -1
  return a*b


print(main())

Solution (Python):
a,b = list(map(int, input().split()))

if a<10 and b<10:
    print(a*b)
else:
    print(-1)

Solution (Python):
n, m = map(int,input().split())

if n < 10 and m < 10:
    print(n*m)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())
if a < 10 and b < 10:
    print(a*b)
else:
    print(-1)

Solution (Python):
import sys
input = sys.stdin.readline
sys.setrecursionlimit(10 ** 7)

A, B = map(int, input().split())

if A < 10 and B < 10:
    print(A * B)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())

if a < 10 and b < 10:
    print(a*b)
else:
    print(-1)

Solution (Python):
A, B = map(int, input().split())

if A <= 9 and B <= 9:
    print(A*B)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())

if a < 10 and b < 10 :
    print(a * b)
else :
    print(-1)

Solution (Python):
import sys
def input():
    return sys.stdin.readline()[:-1]
a,b=map(int,input().split())
if a<10 and b<10:
    print(a*b)
else:
    print(-1)

Solution (Python):
a,b=map(int,input().split())
if a>9 or b >9:
    print(-1)
else:
    print(a*b)

Solution (Python):
n, m = (int(_) for _ in input().split())
if max(n,m) >= 10:
    print(-1)
else:
    print(n*m)

Solution (Python):
a,b = map(int, input().split())
ans=a*b
if a>=10 or b >=10:
    print(-1)
else:
    print(ans)

Solution (Python):
A, B = map(int, input().split())
if A < 10 and B < 10:
    print(A*B)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())
if 1<=a<=9 and 1<=b<=9:
    print(a*b)
else:
    print(-1)

Solution (Python):

def main():
    Input = [input() for i in range(1)]
    
    A,B = list(map(int,Input[0].split()))
    if A>9 or B>9:
        print(-1)
    else:
        print(A*B)
    


if __name__ == "__main__":
    main()

Solution (Python):
a, b = map(int, input().split())

if a <= 9 and b <= 9:
    print(a * b)
else:
    print(-1)

Solution (Python):
def main():
    A, B = (int(i) for i in input().split())
    if A > 9 or B > 9:
        print(-1)
    else:
        print(A*B)


if __name__ == '__main__':
    main()

Solution (Python):
A, B = map(int,input().split())
if A <= 9 and B<= 9 :
    print(A*B)
else:
    print(-1)

Solution (Python):
a,b = map(int, input().split())
if 1 <= a <= 9 and 1 <= b<=9:
    print(a*b)
else:
    print(-1)

Solution (Python):
a,b=map(lambda x: int(x), input().split())
if a>=10 or b>=10:
    print(-1)
else:
    print(a*b)

Solution (Python):
a,b=map(int,input().split())
if a>9 or b>9:
  print(-1)
else:
  print(a*b)

Solution (Python):
A, B= map(int,input().split())

if max(A,B)>9:
    print(-1)
else:
    print(A*B)

Solution (Python):
a,b = map(int,input().split())
if a<=9 and b<=9:
    print(a*b)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())
if a>9 or b>9:
    print((-1))
else:
    print(a*b)

Solution (Python):
a,b=map(int,input().split());print(-1 if max(a,b)>9 else a*b)

Solution (Python):
a, b = (int(x) for x in input().split())
print(a*b) if a < 10 and b < 10 else print(-1)

Solution (Python):
import sys
sys.setrecursionlimit(1000000)
from math import factorial, ceil, floor
from bisect import bisect_right as bsr
from operator import itemgetter as ig
from collections import defaultdict as dd
from collections import deque, Counter as cnt


args = None
INF = float("inf")
MOD = int(1e9 + 7)
def input(*ps):
    if type(ps[0]) is list:
        return [input(*ps[0][:-1]) for _ in range(ps[0][-1])]
    elif len(ps) == 1:
        return ps[0](next(args))
    else:
        return [p(next(args)) for p in ps]
def nlist(n, v):
    if not n: return [] if type(v) is list else v
    return [nlist(n[1:], v) for _ in range(n[0])]


def main():
    A, B = input(int, int)
    if A < 1 or 9 < A or B < 1 or 9 < B:
        print(-1)
    else:
        print(A * B)
    
    return

if __name__ == '__main__':
    args = iter(sys.stdin.read().split())
    main()

Solution (Python):
A,B=map(int,input().split())
if A<10 and B<10:
  print(A*B)
else:
  print(-1)

Solution (Python):
A, B = map(int, input().split())
if A >= 10 or B >= 10:
    print(-1)
else:
    print(A*B)

Solution (Python):
a, b = map(int, input().split())
if a < 10 and b < 10:
  print(a*b)
else:
  print(-1)

Solution (Python):
a,b = map(int,input().split())

if a<=9 and b<=9:
    print(a*b)
else:
    print(-1)

Solution (Python):
def main():
    A, B = map(int, input().split())
    if 1 <= A <= 9 and 1 <= B <= 9:
        print(A * B)
    else:
        print(-1)

if __name__ == "__main__":
    main()

Solution (Python):
A, B = map(int, input().split())
if A < 10 and B < 10:
    print(A*B)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())
if a >= 10 or b >= 10:
    print(-1)
else:
    print(a*b)

Solution (Python):
def read():
    A, B = list(map(int, input().strip().split()))
    return A, B

def solve(A, B):
    if A <= 9 and B <= 9:
        return A * B
    else:
        return -1

if __name__ == '__main__':
    inputs = read()
    print("%d" % solve(*inputs))

Solution (Python):
a,b = map(int,input().split())
if a>9 or b>9:
  print(-1)
else:
  print(a*b)

Solution (Python):
a, b = map(int, input().split())

if a >= 10 or b >= 10:
    print(-1)
else:
    print(a*b)

Solution (Python):
a, b = map(int, input().split())
if (a <= 9 and b <= 9):
    print(a*b)
else:
    print("-1")

Solution (Python):
A,B=map(int,input().split())
if A<=9 and B<=9:
    print(A*B)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())
if a < 10 and b < 10:
  print(a * b)
else:
  print(-1)

Solution (Python):
a,b = map(int,input().split())

if a < 10 and b < 10:
	print(a*b)
else:
	print(-1)

Solution (Python):
import sys
input = sys.stdin.readline


def main():
    A, B = map(int, input().split())
    if A <= 9 and B <= 9:
        print(A*B)
    else:
        print(-1)


if __name__ == '__main__':
    main()

Solution (Python):
[a,b] = [int(i) for i in input().split()]
if a < 10 and b < 10:
    print(a*b)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())
if a <= 9 and b <= 9:
    print(a*b)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split( ))
if 1<=a <=9 and 1<=b<=9:
    print(a*b)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split(' '))

if 0 < a and a < 10 and 0 < b and b < 10:
    print(a * b)
else:
    print('-1')

Solution (Python):
a, b = map(int, input().split())
if a > 9 or b > 9:
    print("-1")
    exit(0)
print(a * b)

Solution (Python):
A, B = map(int, input().split())

if A <= 9 and B <= 9:
	print(A*B)
else:
	print(-1)

Solution (Python):
a, b = map(int, input().split())
if a > 9 or b > 9:
    print(-1)
else:
    print(a * b)

Solution (Python):

a, b = map(int, input().split())
if a >= 10 or b >= 10:
    print(-1)
else:
    print(a * b)

Solution (Python):
a, b = map(int, input().split() )

if 1 <= a <= 9 and 1 <= b <= 9:
    print(a*b)
else:
    print(-1)

Solution (Python):

import sys
input = sys.stdin.buffer.readline


from collections import defaultdict

INF = float("inf")

def getlist():
	return list(map(int, input().split()))


def main():
	A, B = getlist()
	if A < 10 and B < 10:
		print(A * B)
	else:
		print(-1)

if __name__ == '__main__':
	main()

Solution (Python):
A,B = map(int,input().split())

if (A < 10 and B < 10) :
    print(A*B)
else :
    print(-1)

Solution (Python):
a, b = map(int, input().split())
if a < 10 and b < 10:
    print(a*b)
else:
    print(-1)

Solution (Python):
A, B = map(int, input().split())
if A < 10 and B < 10:
    print(A * B)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())

if 1 <= a <= 9 and 1<= b <= 9:
    print(a*b)
else:
    print("-1")

Solution (Python):
A,B=map(int,input().split())
print(A*B if A<=9 and B<=9 else '-1')

Solution (Python):
a,b = map(int, input().split())
print(a*b if a < 10 and b < 10 else -1)

Solution (Python):
a,b=map(int,input().split())

if 1<=a<=9 and 1<=b<=9:
	print(a*b)
else:
	print(-1)

Solution (Python):

import sys
sys.setrecursionlimit(10**8)
input = sys.stdin.readline
INF = 10**9

a, b = [int(item) for item in input().split()]
if a < 10 and b < 10:
    print(a*b)
else:
    print(-1)

Solution (Python):
A, B = map(int, input().split())
if A < 10 and B < 10:
    print(A * B)
else:
    print(-1)

Solution (Python):
a,b=map(int,input().split())
print(a*b if a<=9 and b <=9 else -1)

Solution (Python):
a,b = map(int,input().split())
if 1 <= a <= 9 and 1 <= b <= 9:
    print(a*b)
else:
    print(-1)

Solution (Python):
def main():
    a, b = map(int, input().split())

    if a > 9 or b > 9:
        ans = -1
    else:
        ans = a * b

    print(ans)


if __name__ == "__main__":
    main()

Solution (Python):


a, b = map(int, input().split())
if a < 10 and b < 10:
    print(a * b)
else:
    print(-1)

Solution (Python):
a,b=map(int,input().split())
if 1<=a<=9 and 1<=b<=9:
  print(a*b)
else:
  print("-1")

Solution (Python):
a,b=map(int, input().split()) 
if a>9 or b>9:
  print(-1)
else:  
  print(a*b)

Solution (Python):
a, b = map(int, input().split())
if a > 9 or b > 9:
    print(-1)
else:
    print(a * b)

Solution (Python):
a,b=map(int,input().split())
if 1<=a<=9 and 1<=b<=9:
    print(a*b)
else:
    print(-1)

Solution (Python):
A, B = map(int, input().split())
if A <= 9 and B <= 9:
  print(A*B)
else:
  print(-1)

Solution (Python):
A, B = map(int, input().split())

if A < 10 and B < 10:
    print(A * B)
else:
    print(-1)

Solution (Python):
a,b = map(int,input().split())

if a >= 10 or b >= 10:
    print(-1)
else:
    print(a*b)

Solution (Python):
from sys import stdin


def input():
    return stdin.readline()[:-1]


def intput():
    return int(input())


def sinput():
    return input().split()


def intsput():
    return map(int, sinput())


a, b = intsput()

if a in range(1, 10) and b in range(1, 10):
    print(a * b)
else:
    print(-1)

Solution (Python):
a,b=map(int,input().split())
if a>9 or b>9:
  ans=-1
else:
  ans=a*b
print(ans)

Solution (Python):
A,B = map(int, input().split())
print(A * B) if A <= 9 and B <= 9 else print(-1)

Solution (Python):
a,b=map(int,input().split())
print(a*b if a<=9 and b<=9 else -1)

Solution (Python):
a, b = map(int, input().split())
if a//10 != 0 or b//10 != 0:
  print(-1)
else:
  print(a*b)

Solution (Python):
a,b = [int(i) for i in input().split()]

if 0 < a < 10 and 0<b<10:
    print(a*b)
else:
    print(-1)

Solution (Python):
a,b=map(int,input().split())

if 1<=a<=9 and 1<=b<=9:
    print(a*b)
else:
    print(-1)

Solution (Python):

a, b = map(int, input().split())
if a <= 9 and b <= 9:
    print(a*b)
else:
    print(-1)

Solution (Python):
A, B = map(int, input().split())

if A >= 10 or B >= 10:
	print("-1")
else:
	print(A * B)