def test_two_opposite_units_annihilate(self):
self.assertEqual("", react("aA"))
def test_two_same_units_remain(self):
self.assertEqual("aa", react("aa"))
def test_wrap_around_reaction_not_allowed(self):
self.assertEqual("Bxxxb", react("AaBxxxb"))
def test_a_more_complex_example(self):
self.assertEqual("dabCBAcaDA", react("dabAcCaCBAcCcaDA"))
def test_two_chain_reactions(self):
self.assertEqual("", react("bAaB"))
def test_two_different_units_remain(self):
self.assertEqual("ab", react("ab"))
self.assertEqual("Ab", react("Ab"))
from string import ascii_lowercase
from part1 import react
if __name__ == '__main__':
with open('input.txt') as f:
polymer = f.read().strip()
results = (len(
react(polymer.replace(letter, '').replace(letter.upper(), '')))
for letter in ascii_lowercase)
print(min(results))