class Cost:
    def _init_(self,price,num):
        self.price=price
        self.num =num
    def sum(self):
        sum = self.price*self.num
        return sum
    if __name__=='__main__':
        price =float(input('请输入格列卫的单价：'))
        num = int(input('请输入购买数量：'))
        cost = Cost(price, num)
        sum =cost.sum()
        print('格列宁单价是{0}元，购买{1}共花费{2}元'.format(price,num,sum))