#calculator 

  def add(v1,v2):
	return v1+v2

  def sub(v1,v2):
	return v1-v2
  def multi(v1,v2):
	return v1*v2
  def div(v1,v2):
	return v1/v2

  def main():
	print "WELCOME TO CYBER CALCULATOR"
	print "--"*10
	print "[1] ADDITION "
	print "[2] SUBSTRACTION"
	print "[3] DIVISION"
	print "[4] MULTIPLICATION"
	inp=raw_input("Please select a functuion :")
	if inp == "1":
		x = input("Value 1 : ")
		y = input("Value 2 : ")
		z = add(x,y)
		print z
		main()
	elif inp == "2":
		x = input("Value 1 : ")
		y = input("Value 2 : ")
		z = sub(x,y)
		print z
		main()
	elif inp == "3":
		x = input("Value 1 : ")
		y = input("Value 2 : ")
		if y == 0:
			print "ERROR : DIVISION BY ZERO"
		else:
			z = div(x,y)
			print z
			main()
	elif inp =="4":
		x = input("Value 1 : ")
		y = input("Value 2 : ")
		z = multi(x,y)
		print z
		main()
	else:
		print "ERROR"

  main()