class SensorData:
    def __init__(self, name):
        self.name = name
        self.readings = []

    def add_reading(self, value):
        if -50 <= value <= 150:
            self.readings.append(value)

    def get_average(self):
        if not self.readings:
            return 0
        return sum(self.readings) / len(self.readings)

sensor = SensorData("Temperature")

sensor.add_reading(20)
sensor.add_reading(180)
sensor.add_reading(40)

print(sensor.get_average())