import math
def total_cost(calls):
    counter = 0
    dict = {}
    for mystr in calls:
        date, time_of_call, call_time = mystr.split()
        dict[date] = dict.get(date, 0) + int(math.ceil(float(call_time) / 60))
    for i in dict.values():
        counter += i if i <= 100 else i * 2 - 100
    return counter



if __name__ == '__main__':
    #These "asserts" using only for self-checking and not necessary for auto-testing
    assert total_cost(("2014-01-01 01:12:13 181",
                       "2014-01-02 20:11:10 600",
                       "2014-01-03 01:12:13 6009",
                       "2014-01-03 12:13:55 200")) == 124, "Base example"
    assert total_cost(("2014-02-05 01:00:00 1",
                       "2014-02-05 02:00:00 1",
                       "2014-02-05 03:00:00 1",
                       "2014-02-05 04:00:00 1")) == 4, "Short calls but money..."
    assert total_cost(("2014-02-05 01:00:00 60",
                       "2014-02-05 02:00:00 60",
                       "2014-02-05 03:00:00 60",
                       "2014-02-05 04:00:00 6000")) == 106, "Precise calls"