using System;

​

abstract class absclass{

    public int AddNumbers (int a, int b)

{

    return a+b;

}

    public abstract int MultiplyNumbers (int a, int b);

}

class derivedclass: absclass{

    public override int MultiplyNumbers(int a,int b ){

        return a*b;

    }

}

​

​

​

​

public class Program

{

    public static void Main()

    {

    derivedclass calc=new derivedclass();

        int result = calc.MultiplyNumbers(7,8);

    Console.WriteLine(result);

    }

}