LCA Problem Revisited (Easy)
Given the hanging tree with n (1 ≤ n ≤ 100) vertices, numbered from 0 to n - 1. You need to answer m (1 ≤ m ≤ 100) queries about the least common ancestor for the given pair of vertices.
The queries are generated next way. Given the numbers a[1], a[2] and numbers x, y and z. The numbers a[3], ..., a[2m] are generated next way: a[i] = (x · a[i-2] + y · a[i-1] + z) mod n. The 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
The first line contains two integers n and m. The root of the tree has number 0. The second line contains n - 1 integers, the i-th of which equals to the parent number of vertex i. The third line contains two integers in the range from 0 to n - 1: a[1] and a[2]. The fourth line contains three integers x, y and z, these numbers are nonnegative and do not exceed 10^9.
Output
Print the sum of vertex numbers - the answers to the queries.