# Input: lines like "<code>: <0 or 1>", then blank line,
#        then lines like "<code> (OR/AND/XOR) <code> -> <code>"
# Output: 2^0 * z00 + 2^1 * z01 + ...

values = {}
rules = {}
z_values = []

found_blank_line = False
file = open("24_input.txt", "r")
for line in file:
  line = line.replace("\n", "")
  if line == "":
    found_blank_line = True
    continue
  if not found_blank_line:
    parts = line.split(": ")
    values[parts[0]] = int(parts[1])
    if parts[0][0] == "z":
      z_values.append(parts[0])
    continue
  parts = line.split(" -> ")
  rules[parts[0]] = parts[1]
  if parts[1][0] == "z":
    z_values.append(parts[1])

z_values = list(set(z_values))

while True:
  remaining_rules = rules.copy()
  for rule in rules:
    parts = rule.split(" ")
    code1, operand, code2, result = parts[0], parts[1], parts[2], rules[rule]
    if code1 in values and code2 in values:
      if operand == "AND":
        values[result] = values[code1] & values[code2]
      if operand == "OR":
        values[result] = values[code1] | values[code2]
      if operand == "XOR":
        values[result] = values[code1] ^ values[code2]
      del remaining_rules[rule]
  rules = remaining_rules
  got_all_z_values = True
  for z_value in z_values:
    if not (z_value in values):
      got_all_z_values = False
      break
  if got_all_z_values:
    break

total = 0
for z_value in z_values:
  if values[z_value] == 1:
    total += 2 ** int(z_value[1:])
print (total)