What does it mean? Well, for my dear dear mon amies, it's normal if you don't understand but I am sure XS will understand it because hers is 225... OI, STOP GIVING GUESSES!!! Okay okay, I will tell you what these series of number means. 120 is the number of staircases needed to walk from the bus terminal at KE to my room! It is considered few when compared to Xiao Shuang (XS)'s. Now, do let me introduce the first few steps of staircases from the terminal.
The last 20 steps are common staircases from the 2nd floor to mine while from the bus terminal until the corridor after the Communal Hall is exactly 100 (is that a coincidence?). So this is how I get my 120.
Besides, along the way up, you can see some small flags which had the names on it... I found mine before 120 but after 90.