B"This is an easier version of the problem with smaller constraints. Korney Korneevich dag up an array a of length n . Korney Korneevich has recently read about the operation bitwise XOR, so he wished to experiment with it. For this purpose, he decided to find all integers x ge 0 such that there exists an increasing subsequence of the array a , in which the bitwise XOR of numbers is equal to x . It didn't take a long time for Korney Korneevich to find all such x , and he wants to check his result. That's why he asked you to solve this problem! A sequence s is a subsequence of a sequence b if s can be obtained from b by deletion of several (possibly, zero or all) elements. A sequence s_1, s_2, ldots , s_m is called increasing if s_1 < s_2 < ldots < s_m . The first line contains a single integer n ( 1 <= n <= 10^5 ). The second line contains n integers a_1, a_2, ldots, a_n ( 0 <= a_i <= 500 ) -- the elements of the array a . In the first line print a single integer k -- the number of found x values. In the second line print k integers in increasing order x_1, x_2, ldots x_k ( 0 <= x_1 < ldots < x_k ) -- found x values. In the first test case: "...