LCA - 2
The hanging tree with n (1 ≤ n ≤ 10^5) vertices numbered from 0 to n - 1 is given. Answer m (1 ≤ m ≤ 10^7) queries about Least Common Ancestor for pair of vertices.
The queries are numbered in the next way. Given values a[1], a[2] and x, y и z. Numbers a[3], ..., a[2m] are generated in the next way:
a[i] = (x * a[i-2] + y * a[i-1] + z) mod n.
First query has the form <a[1], a[2]>. If the answer to the (i - 1)-th query is v, then the i-th query has the form <(a[2i-1] + v) mod n, a[2i]>.
Input
First line contains two numbers n and m. The root of the tree has number 0. Second line contains n - 1 integers, i-th of these numbers equals to the parent of the vertex i. Third line contains two integers in the range from 0 to n - 1: a[1] and a[2]. Fourth line contains three integers: x, y and z, they are non-negative and no more than 10^9.
Output
Print the sum of the vertex numbers - the answers to all queries.