LCA

#include <bits/stdc++.h>
using namespace std;

#define endl "\n"
#define ll long long

constexpr int N = 1e5+1, L = 18;

vector<int> dp[N], g[N];
int tin[N], tout[N], a[2*N], t=0;

void dfs(int v, int p = 0)
{
  tin[v]=++t;
  dp[v][0] = p;
  for (int i = 1; i < L; i++)
  {
    dp[v][i] = dp[dp[v][i-1]][i-1];
  }
  for(auto u:g[v])
  {
    if (u!=p)
      dfs(u, v);
  }
  tout[v]=++t;
}

bool upper(int a, int b)
{
  return (tin[a]<=tin[b]&&tout[a]>=tout[b]);
}


int lca(int a, int b)
{
  if (upper(a, b)) return a;
  if (upper(b, a)) return b;
  for (int i = L-1; i >= 0; i--)
  {
    if(!upper(dp[a][i], b))
      a = dp[a][i];
  }
  return dp[a][0];
}

void change_root(int r)
{

}


void Solve()
{
  ll n, m, x, y, z, ans = 0, la = 0;
  cin >> n >> m;
  for (int i = 1; i < n; i++)
  {
    int par;
    cin >> par;
    g[par].push_back(i);
  }
  cin >> a[0] >> a[1] >> x >> y >> z;
  for (int i = 2; i < 2*m; i++)
  {
    a[i] = (x*a[i-2]+y*a[i-1]+z)%n;
  }
  dfs(0);
  for(int i = 1; i < 2*m; i+=2)
  {
    la = lca((a[i-1]+la)%n, a[i]);
    ans+=la;
  }
  cout << ans;
  return;
}

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    Solve();
    return 0;
}