class Tetel():
    def __init__(self, f):
        # input file
        self.f = open(f, 'rb')
        # processed data
        self.data = self.process_data(self.f)

    def process_data(self, file):
        """processes a text file, coverts to integers also"""
        return [int(f) for f in file]

    def get_max(self, data):
        """returns maximum of a list"""
        return max(data)

    def get_sum(self, data):
        """returns sum of a list"""
        return sum(data)

    def filter_data(self, data, f):
        """returns elements of a list that return True to a function"""
        return [elem for elem in data if f(elem)]

    def osszegez(self):
        """returns sum"""
        return self.get_sum(self.data)

    def maxker(self):
        """returns max"""
        return self.get_max(self.data)

    def feltmaxker(self, f):
        """returns max of filter_data's returned list"""
        return self.get_max(self.filter_data(self.data, f))

    def szamlal(self, f):
        """returns length of filter_data's returned list"""
        return len(self.filter_data(self.data, f))