Olesya loves numbers consisting of n digits, and Rodion only likes numbers that are divisible by t. Find some number that satisfies both of them.

Your task is: given the n and t print an integer strictly larger than zero consisting of n digits that is divisible by t. If such number doesn't exist, print  - 1.

Input

The single line contains two numbers, n and t (1 ≤ n ≤ 100, 2 ≤ t ≤ 10) — the length of the number and the number it should be divisible by.

Output

Print one such positive number without leading zeroes, — the answer to the problem, or  - 1, if such number doesn't exist. If there are multiple possible answers, you are allowed to print any of them.

Examples

Input

3 2


Output

712
"""
from time import*
import random
money = 10000
cheat = input("Enter Cheat code if you know it: ")
if cheat == "SAHAR":
	money += 100000
	print("--Your balans 110000rub--")
print("You have",str(money)+"rub")
ques = input("Magazines or VulkanKazino or 1xbet:")
if ques == "1xbet":
	stavki = int(input("How many stavka you want?"))
	for i in range(stavki):
		stav = input("Input your color! :")
		mon = int(input("Money :"))
		sides = ["black","black","black","red","red","green"]
		money -= mon
		die_1 = random.choice(sides)
		if die_1 == stav:
			if stav == "black":
				money += mon*2
				print("YOU WIN")
				print("You have %.1f rub" %money)
				print()
			if stav == "red":
				money += mon*3
				print("YOU WIN")
				print("You have %.1f rub" %money)
				print()
			if stav == "green":
				money += mon*5
				print("YOU WIN")
				print("You have %.1f rub" %money)
				print()
		else:
			money +=0
			print("YOU LOSE")
			print("You have %.1f rub" %money)
elif ques == "VulkanKazino":
	
	
	pass
#####################################
s = int(input("Choise: CS:GO market = 1 , M.video = 2 , Kayhon = 3   :"))
if s == 1:
	print("----Welcome----")
	while 1:
		print("You have %.1f rub in your Wallet" %money)
		mag = int(input("Choise: 1) M4A1 -> Howl = 50000rub  ,2) AWP -> Afrikan = 50rub  ,3) ak47 -> Firesnake = 10000rub  ,4) Karambit -> ulraviolet = 20000rub   ,5) USP-S-> Kings = 100rub , 0)EXIT from magazine:"))
		if mag == 1:
			if money - 50000 < 0:
				print("Sorry you don't have a money((")
				break
			else:
				money -= 50000
				print("Tranzation succesfull, you have %.1f rub in your wallet"%money)
				print()				
		elif mag == 2:
			if money - 50 < 0:
				print("Sorry you don't have a money((")
				break
			else:
				money -= 50
				print("Tranzation succesfull, you have %.1f rub in your wallet"%money)
		elif mag == 3:
			if money - 10000 < 0:
				print("Sorry you don't have a money((")
				break
			else:
				money -= 10000
				print("Tranzation succesfull, you have %.1f rub in your wallet"%money)
		
		elif mag == 4:
			if money - 20000 < 0:
				print("Sorry you don't have a money((")
				break
			else:
				money -= 20000
				print("Tranzation succesfull, you have %.1f rub in your wallet"%money)
		elif mag == 5:
			if money - 100 < 0:
				print("Sorry you don't have a money((")
				break
			else:
				money -= 100
				print("Tranzation succesfull, you have %.1f rub in your wallet"%money)
			if mag == 0:
				break
#######################################################################################
elif s == 2:
	print("------------------------------------------------------Welcome to M.video--------------------------------------------------")
	while 1:
		print("You have %.1f rub in your Wallet" %money)
		mag1 = int(input("notebooks = 1 , PC = 2 , Game Series PC = 3 , telephones = 4, Exit = 0"))
		if mag1==0:
			break
		if mag1 == 1:
			notebook = int(input("Lenovo ideapad310 : 35000rub = 1 , HP jet black : 30000rub = 2 , fujitsu : 20000rub = 3"))
			################################################################################################################
			if notebook == 1:
				lenovo = int(input("Buy = 1 , Show characters = 2"))
				if lenovo ==  1:
					if money - 35000 < 0:
						print("Sorry you don't have a money((")
						break
					else:
						money -= 35000
						print("Tranzation succesfull, you have %.1f rub in your wallet"%money)
				else:
					print("Color: Silver","\n","RAM:12gb","\n","ROM:1TB","\n","VideoCard:Nvidia Geforce 930MX and intelHDgraphics9700")
					povt = int(input("Do you want to buy it?: YES = 1 , NO = 2"))
					if povt == 1:
						if money - 35000 < 0:
							print("Sorry you don't have a money((")
							break
						else:
							money -= 35000
							print("Tranzation succesfull, you have %.1f rub in your wallet"%money)
			####################################################################################
			if notebook == 2:
				hp = int(input("Buy = 1 , Show characters = 2"))
				if hp ==  1:
					if money - 30000 < 0:
						print("Sorry you don't have a money((")
						break
					else:
						money -= 30000
						print("Tranzation succesfull, you have %.1f rub in your wallet"%money)
				else:
					print("Color: Black","\n","RAM:8gb","\n","ROM:1TB","\n","VideoCard:AMD HD Graphics8100")
					povt = int(input("Do you want to buy it?: YES = 1 , NO = 2"))
					if povt == 1:
						if money - 30000 < 0:
							print("Sorry you don't have a money((")
							break
						else:
							money -= 30000
							print("Tranzation succesfull, you have %.1f rub in your wallet"%money)
			######################################################################################
			if notebook == 3:
				fujit = int(input("Buy = 1 , Show characters = 2"))
				if fujit == 1:
					if money - 20000 < 0:
						print("Sorry you don't have a money((")
						break
					else:
						money -= 20000
						print("Tranzation succesfull, you have %.1f rub in your wallet"%money)
				else:
					print("Color: Black","\n","RAM:4gb","\n","ROM:500GB","\n","VideoCard:IntelHD graphics3500")
					povt = int(input("Do you want to buy it?: YES = 1 , NO = 2"))
					if povt == 1:
						if money - 20000 < 0:
							print("Sorry you don't have a money((")
							break
						else:
							money -= 20000
							print("Tranzation succesfull, you have %.1f rub in your wallet"%money)
				
		if mag1 == 2:
			pc = int(input("1) DELL = 100000 , 2)ASUS = 60000 , 3)Apple = 500000 , 4)Lenovo = 300000"))
			############################################################################################
			if pc == 1:
				pc = int(input("Buy = 1 , Show characters = 2"))
				if pc ==  1:
					if money - 100000 < 0:
						print("Sorry you don't have a money((")
						break
					else:
						money -= 100000
						print("Tranzation succesfull, you have %.1f rub in your wallet"%money)
				else:
					print("Color: black","\n","RAM:32gb","\n","ROM:2TB","\n","VideoCard:Nvidia Geforce GTX 1070TI")
					povt = int(input("Do you want to buy it?: YES = 1 , NO = 2"))
					if povt == 1:
						if money - 100000 < 0:
							print("Sorry you don't have a money((")
							break
						else:
							money -= 100000
							print("Tranzation succesfull, you have %.1f rub in your wallet"%money)
"""
"""
n=int(input())
while n>5:
    n = n - 4
    s=n%2
    n=(n-s)/2
if n==1:
	print('Sheldon')
if n==2:
	print('Leonard')
if n==3:
	print('Penny') 
if n==4:
	print('Rajesh')
if n==5:print('Howard')
"""
n, t = map(int, input().split())
if n == 1 and t == 10:
    print(-1)
elif n == 1:
    print(t)
else:
    print(t * (10**(n - 1) // t + 1))
