You will be given a passage with an enumerated set of facts, a question of form 'Where is <person_name>?', and its answer. The task is to identify a supporting fact that is necessary to answer the question. The output would be the corresponding fact number.
Q: Passage: Fact 1- Daniel went to the bedroom. Fact 2- John went back to the kitchen. Fact 3- John moved to the bedroom. Fact 4- Mary travelled to the office. Fact 5- Sandra went to the office. Fact 6- Sandra went back to the hallway. Question: Where is Mary? Answer: office
A: 
Fact 4