Evan is working two summer jobs, making $10 per hour babysitting and making $8 per hour walking dogs. In a given week, he can work no more than 16 total hours and must earn no less than $140. If Evan worked 12 hours babysitting, determine all possible values for the number of whole hours walking dogs that he must work to meet his requirements. Your answer should be a comma separated list of values. If there are no possible solutions, submit an empty answer.