Three people went to live in a hotel together, because there was only one room left, so the boss asked them to live together for ten yuan each! Because the hotel implemented preferential activities, the boss later asked Xiao Er to refund them five dollars. Because Xiao er was greedy, he only returned three yuan, and Xiao er swallowed two yuan himself! Such a lovely friend, each of the three passengers paid nine yuan, and one * * * twenty-seven yuan plus two * * * twenty-nine yuan was swallowed by Xiao Er. Where is the small one yuan?