Question 140
What is the least possible value of
$$
(x_1 - x_2)^2 + (x_2 - x_3)^2 + \dots + (x_{n-1} - x_n)^2 + (x_n - x_1)^2,
$$
if $x_1, x_2, \dots, x_n$ are distinct integer numbers.
$$
(x_1 - x_2)^2 + (x_2 - x_3)^2 + \dots + (x_{n-1} - x_n)^2 + (x_n - x_1)^2,
$$
if $x_1, x_2, \dots, x_n$ are distinct integer numbers.