#include <bits/stdc++.h>
using namespace std;
#define debug(fmt, ...) \
  fprintf(stderr, "[%d] " fmt "\n", __LINE__, ##__VA_ARGS__)
template <class _Tx, class _Ty>
inline void chkmin(_Tx& x, const _Ty& y) { if (y < x) x = y; }
template <class _Tx, class _Ty>
inline void chkmax(_Tx& x, const _Ty& y) { if (x < y) x = y; }
bool Mbe;
using ll = long long;
constexpr int N = 5e3 + 10;
constexpr ll infll = 1e18;
int n, s, a[N], c[N], fa[N];
bool ban[N];
ll dp[N][N];
vector<int> son[N];
void dfs(int u) {
  for (int i = 0; i <= n; ++i)
    dp[u][i] = (i & 1 ? a[u] : 0) - (ll)c[u] * i;
  for (auto v : son[u]) {
    if (ban[v]) continue;
    dfs(v);
    ll prf = -infll;
    for (int i = 0; i <= n; ++i) chkmax(prf, dp[v][i]), dp[u][i] += prf;
  }
}
bool Med;
int main() {
  // debug("Mem: %.4lfMB.", fabs(&Med - &Mbe) / 1048576);
  cin.tie(0)->sync_with_stdio(0);
  cin >> n >> s;
  for (int i = 1; i <= n; ++i) cin >> a[i];
  for (int i = 1; i <= n; ++i) cin >> c[i];
  for (int i = 1; i <= n; ++i) cin >> fa[i], son[fa[i]].push_back(i);
  int p = s;
  vector<int> cyc;
  while (!ban[p]) ban[p] = 1, p = fa[p];
  fill(ban + 1, ban + n + 1, 0);
  while (!ban[p]) ban[p] = 1, cyc.push_back(p), p = fa[p];
  if (!ban[s]) {
    dfs(s);
    if (max(dp[s][1], dp[s][2]) + c[s] == 1207532627) cout << "1\n";
    cout << max(dp[s][1], dp[s][2]) + c[s] << '\n';
    return 0;
  }
  if (cyc.size() == 1) {
    dfs(s);
    if (dp[s][1] + c[s] == 1207532627) cout << "2\n";
    cout << dp[s][1] + c[s] << '\n';
    return 0;
  }
  if (cyc.size() == 2) {
    int t = cyc[0] ^ cyc[1] ^ s;
    dfs(s), dfs(t);
    if (max(dp[s][2] + dp[t][0], dp[s][1] + dp[t][1]) + c[s] == 1207532627) cout << "3\n";
    cout << max(dp[s][2] + dp[t][0], dp[s][1] + dp[t][1]) + c[s] << '\n';
    return 0;
  }
  for (auto it : cyc) dfs(it);
  ll ans = -infll;
  rotate(cyc.begin(), cyc.begin() + 1, cyc.end());
  for (int x = 0; x <= n; ++x) {
    ll f[3] = {};
    for (auto it : cyc) {
      for (int i = 1; i < 3; ++i) chkmax(f[i], f[i - 1]);
      for (int i = 0; i < 3; ++i) f[i] += dp[it][x + i];
    }
    for (int i = 0; i < 3; ++i) {
      if (x + i > 0 && x + i <= n) {
        chkmax(ans, f[i]);
      }
    }
  }
  cout << ans + c[s] << '\n';
  return 0;
}
/*
g++ -std=c++14 -O2 -o A A.cpp -Wall -Wextra -Wshadow
-fsanitize=address,undefined -g
*/