Three friends check into a hotel room that costs $30. They each contribute $10. Later, the manager realizes the room should only cost $25 and gives $5 to the bellboy to return. The bellboy, unable to split the $5 evenly among three friends, gives them $1 each and keeps $2 for himself. Now, each friend has paid $9 (totaling $27), and adding the $2 the bellboy kept makes $29. What happened to the missing dollar?