class Deque:

    def __init__(self):
        self.list = []

    def isEmpty(self) -> bool:
        return len(self.list) == 0

    def append(self, value: int) -> None:
        self.list.append(value)

    def appendleft(self, value: int) -> None:
        self.list = [value] + self.list

    def pop(self) -> int:
        if len(self.list) > 0:
            last_element = self.list[-1]
            self.list = self.list[:-1]
            return last_element
        return - 1


    def popleft(self) -> int:
        if len(self.list) > 0:
            first_element = self.list[0]
            self.list = self.list[1:]
            return first_element

        return -1