Видеоразбор олимпиадной задачи на уравнение в целых числах.

Whole-channel inclusion: Математические этюды is an honest teaching channel (title sample + 3 transcripts read: All sampled videos lack transcripts, but titles/descriptions match the channel's established pattern of rigorous math problem-solving and lecture content, consistent with the 'whole' title-sample verdict.); this title passed a strict title check (sonnet) after a labelling pass.