#!/usr/bin/env python
from datetime import datetime
import re

RE_BEGIN = re.compile("^\[(.*)\] Guard #(\d+) begins shift$")
RE_SLEEP = re.compile("^\[(.*)\] falls asleep$")
RE_AWAKE = re.compile("^\[(.*)\] wakes up$")

guards = dict()

def read_input():
    with open('input.txt', 'r') as f:
        data = f.read().splitlines()
        return sorted(data)

def convert_time(data):
    return datetime.strptime(data, '%Y-%m-%d %H:%M')

def guard_stop_shift(guard, date):
    guard_awake(guard, date)

def guard_start_shift(guard, date):
    if guard is None:
        return
    if guard not in guards:
        guards[guard] = {
            'guard': guard,
            'state': 'awake',
            'min': [0]*60,
            'sleep': 0,
            'last_time': None
        }
    guard_awake(guard, date)

def guard_sleep(guard, date):
    if guard is None:
        return
    guards[guard]['state'] = 'sleep'
    guards[guard]['last_time'] = date

def guard_awake(guard, date):
    if guard is None:
        return
    if guards[guard]['state'] in ['awake']:
        guards[guard]['last_time'] = date
        return

    m = int((date - guards[guard]['last_time']).total_seconds() / 60)
    m1 = guards[guard]['last_time'].minute
    for x in range(m):
        m2 = (x + m1) % 60
        guards[guard]['min'][m2] += 1
    guards[guard]['sleep'] += m
    guards[guard]['state'] = 'awake'
    guards[guard]['last_time'] = date


current_guard = None
for line in read_input():
    m = RE_BEGIN.match(line)
    if m:
        d = convert_time(m.group(1))
        guard_stop_shift(current_guard, d)
        current_guard = (int)(m.group(2))
        guard_start_shift(current_guard, d)
        continue

    m = RE_SLEEP.match(line)
    if m:
        d = convert_time(m.group(1))
        guard_sleep(current_guard, d)
        continue

    m = RE_AWAKE.match(line)
    if m:
        d = convert_time(m.group(1))
        guard_awake(current_guard, d)
        continue

    print(line)
    raise Exception('unpasable line')

max_min = 0
max_guard = None

for g in guards.values():
    m = max(g['min'])
    if m > max_min:
        max_guard = g
        max_min = m

max_min_pos = [i for i, j in enumerate(max_guard['min']) if j == max_min]

print(max_guard['guard'] * max_min_pos[0])