class HitCounter:

    def __init__(self):
        self.counter = deque()

    def hit(self, timestamp: int) -> None:
        self.counter.append(timestamp)

    def getHits(self, timestamp: int) -> int:

        while len(self.counter) > 0 and self.counter[0] <= timestamp - 300:
            self.counter.popleft()

        return len(self.counter)