class Transformations:
    def __init__(self, name, arr) -> None:
        self.name = name
        self.arr = list(arr)

    def append(self, item) -> None:
        self.arr.append(item)

    def __sub__(self, other):
        return Transformations(self.name[:6] + other.name[-3:],
                               list(map(filter(lambda x: x not in other.arr, self.arr))))

    def __itruediv__(self, n):
        self.arr = self.arr[:n]

    def __lt__(self, other):
        if len(self.arr) != len(other.arr):
            return len(self.arr) < len(other.arr)
        elif sorted(self.arr) != sorted(other.arr):
            return sorted(self.arr) < sorted(other.arr)
        else:
            return self.name < other.name

    def __call__(self, n):
        return tuple(self.arr[:n])

    def __str__(self):
        return self.name