# simple counter class

class Counter:
    def __init__(self, initialvalue = 0):
        self.counter = initialvalue

    def decr(self, decrvalue = -1):
        self.counter += decrvalue
        return self.counter
    
    def incr(self, incrvalue = 1):
        self.counter += incrvalue
        return self.counter        

    def value(self):
        return self.counter

    def set(self, setvalue):
        self.counter = setvalue
        return self.counter