German Conquers now

Consider a sequence $a_1, a_2, . . . , a_{2018}$ of positive integers. Extend it periodically to an infinite sequence $a_1, a_2, . . .$ by defining $a_{i+2018} = a_i$ for all $i \ge 1$ . If

$\large\ { a }_{ 1 } \le { a }_{ 2 } \le ...\le a_{ 2018 } \le a_1 + 2018$

and

$\large\ { a }_{ { a }_{ i } } \le i + 2017$ ,

for $i = 1, 2, 3, ... , 2018$ .

Maximise ${ a }_{ 1 } + { a }_{ 2 } + ...+ a_{ 2018 }$ .