Input : 100 200 300 and output is 2 40. Why?

Question

https://code.sololearn.com/c89J1FCAyB7p/?ref=app

Answer 1

on successfully receiving and assigning inputs obtained scanf returns the number of inputs received so that is assigned to 'a' hence a will be 2. I'am not sure about second output its actually giving 3.

Answer 2

Actually the output 40 is confusing. I have no explanation for this.