Hi, I have a question for which the answer is provided but I don't know how it is derived, could you help to explain it step by step please?

Thank you in advance!

Suppose that Romeo has the utilityr function U - 553521 and Juliet has the utilityr function U - 51355 , where 53 is Romeo's spaghetti consumption and SJ is Juliet's. Thevr have as units of spaghetti to divide between them. Romeo would want to give Juliet some spaghetti if he had more than 26 units of spaghetti. Juliet would want to give Romeo some spaghetti if she had more than 23 units. Juliet would want to give Romeo some spaghetti if she had more than 30 units of spaghetti. Romeo would want to give Juliet some spaghetti if he had more than 18 units of spaghetti. Romeo and Juliet would never disagree about how to divide the spaghetti