Paul is having a wedding in San Francisco. He invites his friend from college John to the wedding. He tells John he will take care of all his travel expenses if he comes to the wedding. John books a first class ticket to San Francisco and shows up for Paul's wedding. After the wedding John asks Paul to reimburse him for the expenses and Paul refuses saying he's already over his budget.

Was there consideration between Paul and John for it to be an enforceable contract? please explain in cirac format