Masala B

Abduahad yaqinda tenglamalar sistemasi mavzusini o'rgandi. Yaqinda u shu mavzu doirasida qiziqarli masalaga duch keldi. Lekin hech bu masalani yecha olmayapti. Siz unga shu masalani yechishda yordam bering

$x_{1} + 4x_{2} + 9x_{3} + 16x_{4} + 25x_{5} + 36x_{6} + 49x_{7} = a$

$4x_{1} + 9x_{2} + 16x_{3} + 25x_{4} + 36x_{5} + 49x_{6} + 64x_{7} = b$

$9x_{1} + 16x_{2} + 25x_{3} + 36x_{4} + 49x_{5} + 64x_{6} + 81x_{7} = c$

$16x_{1} + 25x_{2} + 36x_{3} + 49x_{4} + 64x_{5} + 81x_{6} + 100x_{7} - ?$

a, b, c sonlari  $(-10^{18} \le a, b, c \le 10^{18} )$

Masala shartida so'ralgan ifodaning qiymatini toping