Hi, the answer for this question is 9$, but I'm unsure of why- I keep getting 37. Could someone please explain the answer?

'At the end of the year, Scarlett Witch Ltd. had accounts payable of $63. At the beginning of the year, Scarlett Witch Ltd. had accounts payable of $40, and during the year they paid off accounts payable amounting to $14. During the year, the inventory bought on credit would be ____ (dollar amount)?