using System;

namespace Example44
{
	class Fraction
	{
		private int numerator;		// numerator
		private int denominator;	// denominator

		public Fraction(int numerator, int denominator)
		{
			this.numerator = numerator;
			this.denominator = denominator;
		}

		public int Numerator
		{
			get { return numerator; }
		}

		public int Denominator
		{
			get { return denominator; }
		}

		public Fraction Add(Fraction f2)
		{
			int x = numerator * f2.Denominator + denominator * f2.Numerator;
			int y = denominator * f2.Denominator;

			Fraction f3 = new Fraction(x, y);

			return f3;
		}

		public Fraction Subtract(Fraction f2)
		{
			int x = numerator * f2.Denominator - denominator * f2.Numerator;
			int y = denominator * f2.Denominator;

			Fraction f3 = new Fraction(x, y);

			return f3;
		}

		public Fraction Multiply(Fraction f2)
		{
			int x = numerator * f2.Numerator;
			int y = denominator * f2.Denominator;

			Fraction f3 = new Fraction(x, y);

			return f3;
		}

		public Fraction Divide(Fraction f2)
		{
			int x = numerator * f2.Denominator;
			int y = denominator * f2.Numerator;

			Fraction f3 = new Fraction(x, y);

			return f3;
		}

		public override string ToString()
		{
			return numerator + "/" + denominator;
		}
	}

	class Test
	{
		static void Main(string[] args)
		{
			Fraction f1, f2, f3;

			f1 = new Fraction(2, 3);
			f2 = new Fraction(4, 5);

			Console.WriteLine("f1 = " + f1.ToString());
			Console.WriteLine("f2 = " + f2.ToString());

			f3 = f1.Add(f2);
			Console.WriteLine("f1 + f2 = " + f3.ToString());

			f3 = f1.Subtract(f2);
			Console.WriteLine("f1 - f2 = " + f3.ToString());

			f3 = f1.Multiply(f2);
			Console.WriteLine("f1 * f2 = " + f3.ToString());

			f3 = f1.Divide(f2);
			Console.WriteLine("f1 / f2 = " + f3.ToString());

		}
	}
}