class Circle {
    private _radius: number;

    constructor(radius: number) {
        this._radius = radius;
    }

    get radius(): number {
        return this._radius;
    }

    set radius(value: number) {
        if (value >= 0) {
            this._radius = value;
        } else {
            console.log("Invalid radius value.");
        }
    }
}

const myCircle = new Circle(5);
myCircle.radius = 10;
console.log(myCircle.radius);

myCircle.radius = -5; // Kimenet: Invalid radius value.
console.log(myCircle.radius);