class Deque:
    'Fast searchable queue'
    def __init__(self):
        self.od = OrderedDict()
    def appendleft(self, k):
        od = self.od
        if k in od:
            del od[k]
        od[k] = None
    def pop(self):
        return self.od.popitem(0)[0]
    def remove(self, k):
        del self.od[k]
    def __len__(self):
        return len(self.od)
    def __contains__(self, k):
        return k in self.od
    def __iter__(self):
        return reversed(self.od)
    def __repr__(self):
        return 'Deque(%r)' % (list(self),)