class Point
    attr_accessor :x,:y
    def initialize(x=0,y=0)
        self.x=x
        self.y=y
    end
    def to_s
        "Point at #{x},#{y}"
    end
end

class Circle
    attr_accessor :x,:y,:r
    def initialize(x=0,y=0,r=0)
        self.x=x
        self.y=y
        self.r=r
    end
    def to_s
        "Circle at #{x},#{y} with radius #{r}"
    end
end