Java – uses an object as a variable in the constructor

I have a question about using objects as variables in constructors It may be simple, but I really can't think of what to do. My java book doesn't really help Said I wanted to

Fraction f3 = new Fraction(1,2);
Fraction f5 = new Fraction(f3);

The constructor of my first object is:

public Fraction(int n,int d)

{
    if (d == 0)
    {
        numerator = 0;
        denominator = 1;
        System.err.println("Error: Invalid Denominator (" + d + ")");
    }
    else if (d < 0)
    {
        int nn = Math.abs(n) * (-1);
        numerator = nn;
        denominator = Math.abs(d);
    }
    else
    {
    numerator = n;
    denominator = d;
    }

}

The constructor of my second object is like this:

public Fraction(Fraction f) 

{

}

I can't figure out how to define a constructor to set a new object to a given object I would appreciate it if someone could give me a hand or some suggestions to solve it

Solution

public Fraction(Fraction f){

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