import time
start = time.time()
file = open('input.txt', 'r')
commands = {}
cached_output = {}
def string_or_int(value):
    if value.isdigit(): return int(value)
    else: return value

def parse_command(output, operator, string):
    splits = string.split(" ")
    commands[output] = {}
    commands[output]['operator'] = operator
    if operator == "ASSIGN":
        commands[output]['value_1'] = string_or_int(splits[0])
    elif operator == "NOT":
        commands[output]['value_1'] = string_or_int(splits[1])
    elif operator == "AND" or operator == "OR" or operator == "LSHIFT" or operator == "RSHIFT":
        commands[output]['value_1'] = string_or_int(splits[0])
        commands[output]['value_2'] = string_or_int(splits[2])
            
for line in file:
    splits = line.split(" ")
    output = splits[len(splits)-1]
    output = output.strip()
    if line.find("NOT") != -1: parse_command(output, "NOT", line)
    elif line.find("AND") != -1: parse_command(output, "AND", line)
    elif line.find("OR") != -1: parse_command(output, "OR", line)
    elif line.find("LSHIFT") != -1: parse_command(output, "LSHIFT", line)
    elif line.find("RSHIFT") != -1: parse_command(output, "RSHIFT", line)
    else: parse_command(output, "ASSIGN", line)
        
def calc_and_cache_output(key):
    if isinstance( key, int ): cached_output[key] = key
    else: cached_output[key] = calc_output(key)
    return cached_output[key]
            
def calc_output(key):
    if key in cached_output: return cached_output[key]
    command = commands[key]
    operator = command['operator']
    if operator == "ASSIGN": return calc_and_cache_output(command['value_1'])
    elif operator == "NOT": return ~calc_and_cache_output(command['value_1'])
    elif operator == "AND": return calc_and_cache_output(command['value_1']) & calc_and_cache_output(command['value_2'])
    elif operator == "OR": return calc_and_cache_output(command['value_1']) | calc_and_cache_output(command['value_2'])
    elif operator == "LSHIFT": return calc_and_cache_output(command['value_1']) << calc_and_cache_output(command['value_2'])
    elif operator == "RSHIFT": return calc_and_cache_output(command['value_1']) >> calc_and_cache_output(command['value_2'])

value = calc_output('a')
print("Value of a is: " + str(value))
cached_output = {}
cached_output['b'] = value
value = calc_output('a')
print("Value of a is: " + str(value))
print(time.time() - start)