What's the earliest bus from Gangnam Station to the Airport?

[kino]

I want to leave Gangnam station to Incheon airport around 6 AM. What's the earliest bus that I can catch?

[kino]

The bus you want to take is number 6009. If you are catching it from Gangnam Station the operating hours are 03:46 AM ~ 08:40 PM. The bus arrives in 15 to 20 minute intervals.  

The bus stop is in the middle of the street away from Exits 10 & 11 of Gangnam Station.

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