class OOPPractice
{
	public static void main(String args[])
	{
		System.out.println("Hello World!!");
		Calc int1 = new Calc();
		Calc int2 = new Calc();

		int1.assign(30);
		int2.assign(5);

		System.out.println(int1.value + " + " + int2.value + " = " + int1.add(int2.value) + "\n");
		System.out.println(int1.value + " - " + int2.value + " = " + int1.subtract(int2.value) + "\n");
		System.out.println(int1.value + " * " + int2.value + " = " + int1.multiply(int2.value) + "\n");
		System.out.println(int1.value + " / " + int2.value + " = " + int1.divide(int2.value) + "\n");
	}
}



class Calc
{
	int value = 0;

	void assign(int number)
	{
		value = number;
	}
	int subtract(int x)
	{
		// value = value - x;
		return value - x;   // This way, the new value is not stored, just returned.
	}


	int multiply(int x)
	{
		value = value * x;
		return value;
	}
	int divide(int x)
	{
		value = value / x;
		return value;
	}
}