using System;

​

public readonly struct Fraction

{

    private readonly int num;

    private readonly int den;

    public Fraction(int numerator, int denominator)   {   num = numerator;   den = denominator;   }

​

    public static 

    public static Fraction operator +(String a, Fraction b) => new Fraction(1,2);

    public static Fraction operator +(Fraction a, String b) => new Fraction(7,8);

    public static Fraction operator -(String a, Fraction b) => new Fraction(3,4);

​

    public override string ToString() => $"{num} / {den}";

}

​

public static class OperatorOverloading

{

    public static void Main()

    {

        var a = new Fraction(5, 4);

        var b = new Fraction(1, 2);

        Console.WriteLine("a" + b);  

        Console.WriteLine(b + "a");  

        Console.WriteLine("a" - b);  

       // Console.WriteLine(b - "a");  

    }

}