a²-2019b = 2019a + b²;
b² - a² = -2019b - 2019a;;
(b - a)(b + a) = -2019(b + a);;
если a ≠ -b, b - a = -2019.
a²-2019b = 2019a + b²;
b² - a² = -2019b - 2019a;;
(b - a)(b + a) = -2019(b + a);;
если a ≠ -b, b - a = -2019.