#!/usr/bin/env python

import re

MONKEYS = []

def parse_factor(old, factor):
    if factor == 'old':
        return old

    return int(factor)

OPS = {
    '*': lambda old, factor: old * parse_factor(old, factor),
    '+': lambda old, factor: old + parse_factor(old, factor),
}

with open('input') as f:
    monkey = {'inspections': 0}

    for line in f:
        if line == "\n":
           MONKEYS.append(monkey)
           monkey = {'inspections': 0}
        elif match := re.match('^Monkey (\d+):$', line):
            monkey['id'] = int(match[1])
        elif match := re.match('^  Starting items:', line):
            _, items = line.rstrip().split(":")
            monkey['items'] = list(map(int, items.split(", ")))
        elif match := re.match('^  Operation: new = old ([\*\+]) (\w+)', line):
            monkey['op_op'] = match[1]
            monkey['op_factor'] = match[2]
        elif match := re.match('^  Test: divisible by (\d+)$', line):
            monkey['test_factor'] = int(match[1])
        elif match := re.match('^    If (true|false): throw to monkey (\d+)$', line):
            monkey['test_'+match[1]] = int(match[2])
        else:
            raise Exception('unhandled line: '+line)
    MONKEYS.append(monkey)

for idx, monkey in enumerate(MONKEYS):
    assert(idx == monkey['id'])

for r in range(1, 21): # round
    for monkey in MONKEYS: # turn
        for item in monkey['items']:
            item = OPS[monkey['op_op']](item, monkey['op_factor'])
            item = item // 3
            if item % monkey['test_factor'] == 0:
                MONKEYS[monkey['test_true']]['items'].append(item)
            else:
                MONKEYS[monkey['test_false']]['items'].append(item)
            monkey['inspections'] = monkey['inspections'] + 1
        monkey['items'] = []

by_inspections = sorted(MONKEYS, key=lambda monkey: monkey['inspections'])

print(by_inspections[-1]['inspections'] * by_inspections[-2]['inspections'])