def test_evaluate_addition(self):
     assert 3 == eval('(+ 1 2)')
 def test_evaluate_empty_expression(self):
     assert None is eval('')
 def test_evaluate_empty_list(self):
     assert None is eval('()')
 def test_evaluate_modulus(self):
     assert 0 == eval('(% 4 4)')
 def test_evaluate_nested(self):
     assert 10 == eval('(- (+ 6 1 (- 10 7) 5) 5)')
 def test_evaluate_pow(self):
     assert 100 == eval('(^ 10 2)')
 def test_evaluate_division(self):
     assert 2 == eval('(/ 6 3)')
 def test_evaluate_multiplication(self):
     assert 10 == eval('(* 5 2)')
 def test_evaluate_subtraction(self):
     assert 1 == eval('(- 2 1)')
import sys
from arithmetic_lang import eval
assert len(sys.argv) >= 2

print(eval(sys.argv[1]))