import sys

data = sys.stdin.read().split()
n, m = int(data[0]), int(data[1])
parents = [0] * n
idx = 2
for i in range(1, n):
    parents[i] = int(data[idx])
    idx += 1
a1, a2 = int(data[idx]), int(data[idx+1])
x, y, z = int(data[idx+2]), int(data[idx+3]), int(data[idx+4])
adj = [[] for _ in range(n)]
for i in range(1, n):
    adj[parents[i]].append(i)
depth = [0] * n
q = [0]
for u in q:
    for v in adj[u]:
        depth[v] = depth[u] + 1
        q.append(v)
up = [[0] * 18 for _ in range(n)]
for i in range(1, n):
    up[i][0] = parents[i]
for k in range(1, 18):
    for i in range(n):
        up[i][k] = up[up[i][k-1]][k-1]
a = [0] * (2 * m + 1)
a[1], a[2] = a1, a2
for i in range(3, 2 * m + 1):
    a[i] = (x * a[i-2] + y * a[i-1] + z) % n
ans = 0
v = 0
for i in range(1, m + 1):
    u = (a[2*i-1] + v) % n
    vq = a[2*i]
    if depth[u] < depth[vq]:
        u, vq = vq, u
    diff = depth[u] - depth[vq]
    for k in range(18):
        if (diff >> k) & 1:
            u = up[u][k]
    if u == vq:
        v = u
    else:
        for k in range(17, -1, -1):
            if up[u][k] != up[vq][k]:
                u = up[u][k]
                vq = up[vq][k]
        v = up[u][0]
    ans += v
print(ans)