#!/usr/bin/env python
#socat tcp-listen:2060,fork exec:./sandbox.py,pty,stderr
import re
num_pattern = re.compile(r'^[\d]{0,4}$')
operator_pattern = re.compile(r'^[\W]+$')
del re


if __name__ == '__main__':
	class Detangle:
		str  = str
		repr = repr
		dir  = dir
		eval = eval
		filter = filter
		log = True
		exclude = {
			'__builtins__': ('print',),
		}
		forbidden = ('__builtins__.open', '__builtins__.file')

		def __init__(self):
			self.intercept('__builtins__')

		def intercept(self, module_str, module = None):
			self.log = False
			module = module if module else self.eval(module_str)
			for f in self.filter(lambda f: not f in self.exclude[module_str], module.__dict__):
				func = self.eval('module.' + f, {'module': module})
				module.__dict__[f] = self.Interceptor(func, module_str + '.' + f, self)
			self.log = True
	
		class Interceptor:
			def __init__(self, orig, func, detangle):
				self.orig = orig
				self.func = func
				self.d    = detangle
				self.to_str  = self.d.str(orig)
				self.to_repr = self.d.repr(orig)
	
			def __call__(self, *args, **kwargs):
				if self.func in self.d.forbidden:
					raise SystemExit('That is forbidden');
				result = self.orig(*args, **kwargs)
				if self.d.log:
					if self.func == '__builtins__.__import__':
						if args[0] not in self.d.exclude:
							raise SystemExit('Sandbox breaking detected.')
						self.d.intercept(args[0], result)
					args   = ', '.join([self.d.repr(p) for p in args])
					kwargs = ', '.join(['{0} = {1}'.format(k, v) for k, v in kwargs.items()])
					param  = args + ', ' + kwargs if kwargs else args
					print('Debug: {0}({1}) # {2}'.format(self.func, param, self.d.repr(result)))
				return result
			
			def __str__(self):
				return self.to_str
	
			def __repr__(self):
				return self.to_repr

	Detangle = Detangle()
	del Detangle
## sandboxed code 
num1 = raw_input('Number 1: ')
num2 = raw_input('Number 2: ')
operator = raw_input('Operator: ')

if not num_pattern.match(num1) or not num_pattern.match(num2):
	raise SystemExit('Number rejected')
if not operator_pattern.match(operator) or len(operator) > 1900:
	raise SystemExit('Operator rejected')
del num_pattern
del operator_pattern
operator = eval(operator) if "'" in operator else operator
print(eval(num1 + operator + num2))