soooo how long was he in jail💔

So i googled how long it takes to become a police officer in south Korea including uni (5 years)... I believe he had started 2nd year in uni near the end, so that would be 4 years (minus the 1 year of uni he already had) and let's just assume he's already had 1 year as a police officer on duty cause he didn't seem like so much of a newbie with the fact he's been to the Cafe as a cop quite a bit already..... sooo roughly 5 years in jail maybe??? My very very wild guess lolol