first come, first served

Translations
первый пришёл, первый обслужен
The tickets are available on a first come, first served basis.
Билеты доступны по принципу: первый пришёл, первый обслужен.
Definitions
A principle or policy that prioritizes those who arrive or request something first, ensuring that they receive service or access before others.
Words
first

adverb
первым
come

verb
приходит
first

adverb
первым
served

verb
обслужен