JAVA - eclipse (else if) help needed [closed]

I'm just a beginner, and I'm completely stuck on my homework... don't be tough, please!

JAVA - eclipse

I have to create a program that emulates an ATM that only gives 20 and 50€ bills:

The 50€ bills have priority (if I want 120, it will be 2 50's and one 20)

I can only use else-if.

Beware, because if I need 60€, it has to be three 20€ bills. Or 110, it can gives me one 50€ and 3 20's...

If I ask something that the ATM can't give with 50's and 20's, it will say it can't.

I got this so far:

System.out.print("Bienvenido de nuevo Sr. Bezos. ¿Qué humilde cantidad le doy? ");

final int dinero = scr.nextInt();



final int b50, b20, r;



b50 = dinero / 50;

r = dinero % 50;

b20 = r / 20;



if (r == 0) 

    System.out.println("Le daré " + b50 + " billetes de 50 euros.");



else if (r != 0 && dinero - b50 \* 50 - b20 \* 20 != 0 && r / 20 != 0 || dinero % 20 == 0) {

    System.out.println("Le daré " + dinero / 20 + " billetes de 20 euros.");

}



if (dinero - b50 \* 50 - b20 \* 20 != 0 && dinero % 20 != 0) {

    System.out.println("Le daré " + b50 + " billetes de 50 euros y " + ((dinero - 10) % 20) + " billetes de 20 euros.");

}

else {

    System.out.println("Lo siento, Sr. Bezos. Este cajero sólo dispone de billetes de 50€ y de 20€.");