Please explain how we get the answer (27) especially how g(b,a) is calculated

java
#1

public class SomeProgram {

public static int g(int a, int b) {
return a - 2 * b;
}

public static int f(int a, int b) {
return b + g(b, a);
}

public static void main(String[] args) {
int a = 9;
int b = 3;
int c = f(b, a) - g(b, a);
System.out.println©;
}
}

#2

Maybe add some System.out.println so you can see step of the calculations?

here:

int a = 9;
int b = 3;

you define a and b, but this are also the name of the parameters for f and g function, which is really confusing