Dervied class Constructor value pass to parent class

Question

I am trying to pass the value from child class to parent class constructor. But

class Class1
{

public Class1(int a, int b) {
this.a = a;
this.b = b;
Console.WriteLine("parentconstructor");
}
}
class Class2: Class1 { 

public Class2(int a, int b): base(a, b) {

Console.WriteLine("childconstructor");
}
}

 

 class program

{

 class2 obj =new class2( 4,5);

Console.ReadLine(); 

}

 

//OUTPUT

//Parentconstructor

//childconstriuctor 

// But excepted child constructor first an second parentconstructor