When "Ai-chan" was merely an I-cup, on Sono 39, her bust was confirmed as 97 cm (38"). She then teased her "Onii-san" that she would need to change her name to "Kei-chan" because of her growing bust size. On Sono 100, her bust was celebrated by Yolley-bu-chan as 100 cm (39") and a K-cup. Going by Japanese bra sizes, a P-cup would be 113 cm (44½").
P-cup
17,839 twe-
actually referring to Idolmaster Shiny Colors' "Producer's Cup" event, which caused P-Cup to trend to many people's confusion and misunderstanding