using System;

public class Student

{

    public Student()  // default constructor

    {

        Console.WriteLine(" this is first default constructor");

    }

    public Student ( int a,int b)

    {

        Console.WriteLine(" This is second constructor : {0}" , (a+b));

    }

    public Student ( int a, int b, int c)

    {

        Console.WriteLine(" This is third constructor : {0} ", (a+b+c));

    }

    public Student( string name)

    {

        Console.WriteLine(" this is fourth constructor ");

    }

    public static void Main()

    {

        Student S1= new Student();

        Student S2= new Student( 45,34);

        Student S3 = new Student ( 34,23,12);

        Student S4= new Student("himani");

        Student S5= new Student ( 67,78);

    }

}