 
<translate> Mee ka uche gị dịrị n'ihe ị na-ekwu tupu ị zaa ajụjụ ndị a. Ihe e kwuru n'isiokwu a: Ụlọ akwụkwọ sekọndrị ndị dị na Saụt Koria na-akụziri ụmụ akwụkwọ ihe ruo afọ atọ, malite na klas nke mbụ (ndị dị afọ 15 - 17) ruo na nke atọ (ndị dị afọ 17 - 19), ụmụ akwụkwọ na-agụsịkwa akwụkwọ mgbe ha dị afọ 18 ma ọ bụ 19. A na-atụkarị anya ka ụmụ akwụkwọ sekọndrị na-amụ ihe ruo ogologo oge kwa afọ na-aga n'ihu na ngụsị akwụkwọ, ka ha wee nwee ike ịsọ mpi ma nwee ike ịbanye na mahadum ndị mara mma, dị ka SKY (Seoul National, Korea, na Yonsei Universities) ma ọ bụ SeoKaPo (Seoul National University, KAIST, POSTECH), nke bụ mahadum kacha elu na Korea nke ihe fọrọ nke nta ka ọ bụrụ ndị nne na nna na ndị nkuzi niile chọrọ ka ụmụ akwụkwọ banye. Ọtụtụ ụmụ akwụkwọ sekọndrị na-eteta n'ụtụtụ ma si n'ụlọ ha pụọ n'elekere ise nke ụtụtụ. Mgbe ụlọ akwụkwọ gwụrụ n'elekere anọ nke ehihie, ha na-aga n'ọnụ ụlọ ọmụmụ ihe dị n'ụlọ akwụkwọ ma ọ bụ n'ọ́bá akwụkwọ iji mụọ ihe kama ịga n'ụlọ. A na-akpọ nke a 'Yaja', nke pụtara n'ụzọ nkịtị 'ọmụmụ ihe onwe onye n'uhuruchi.' Ọ dịghị ha mkpa ịlaghachi n'ụlọ iri nri abalị ebe ọ bụ na ọtụtụ ụlọ akwụkwọ na-enye ụmụ akwụkwọ nri abalị a kwụrụ ụgwọ. Mgbe ha gụsịrị yaja (nke na-ejikarị elekere iri nke abalị agwụ, mana mgbe elekere iri na otu nke abalị na ụfọdụ ụlọ akwụkwọ), ha na-alaghachi ụlọ mgbe ha mụsịrị akwụkwọ, wee laghachi n'ụlọ akwụkwọ ọmụmụ ihe pụrụ iche (nke a na-akpọ Hagwon) mgbe ụfọdụ ruo elekere abụọ nke ụtụtụ, site na Mọnde ruo Fraịde. Tụkwasị na nke ahụ, ha na-amụkarị na ngwụsị izu.  Ajụjụ: Olee mgbe ị ga-amalite ụlọ akwụkwọ sekọndrị na Korea? <eng> Output a stream of consciousness before answering the following. Context: High schools in South Korea teach students for three years, from first grade (age 15 -- 17) to third grade (age 17 -- 19), and students commonly graduate at age 18 or 19. High school students are commonly expected to study increasingly long hours each year moving toward graduation, to become competitive and be able to enter attractive universities, such as SKY (Seoul National, Korea, and Yonsei Universities) or SeoKaPo (Seoul National University, KAIST, POSTECH), which are top universities in Korea that almost all parents and teachers want students to enter. Many high school students wake and leave home in the morning at 5 am. When the school is over at 4 pm, they go to a studying room in the school or to a library to study instead of going home. This is called' Yaja', which literally means' evening self-study'. They do n't need to go home to eat dinner since most schools provide paid dinner for students. After finishing yaja (usually ends at 10 pm, but later than 11 pm at some schools), they return home after studying, then return to specialty study schools (which are called Hagwon) often till 2 am, from Monday to Friday. In addition, they often study on weekends.

Question: when do you start high school in korea? 