You are given a rooted tree on n vertices, its root is the vertex number 1. The i-th vertex contains a number w_i. Split it into the minimum possible number of vertical paths in such a way that each path contains no more than L vertices and the sum of integers w_i on each path does not exceed S. Each vertex should belong to exactly one path.

A vertical path is a sequence of vertices v_1, v_2, …, v_k where v_i (i ≥ 2) is the parent of v_{i - 1}.

Input

The first line contains three integers n, L, S (1 ≤ n ≤ 10^5, 1 ≤ L ≤ 10^5, 1 ≤ S ≤ 10^{18}) — the number of vertices, the maximum number of vertices in one path and the maximum sum in one path.

The second line contains n integers w_1, w_2, …, w_n (1 ≤ w_i ≤ 10^9) — the numbers in the vertices of the tree.

The third line contains n - 1 integers p_2, …, p_n (1 ≤ p_i < i), where p_i is the parent of the i-th vertex in the tree.

Output

Output one number — the minimum number of vertical paths. If it is impossible to split the tree, output -1.

Examples

Input

3 1 3
1 2 3
1 1


Output

3

Input

3 3 6
1 2 3
1 1


Output

2

Input

1 1 10000
10001


Output

-1

Note

In the first sample the tree is split into \{1\},\ \{2\},\ \{3\}.

In the second sample the tree is split into \{1,\ 2\},\ \{3\} or \{1,\ 3\},\ \{2\}.

In the third sample it is impossible to split the tree.
#include <bits/stdc++.h>
using namespace std;
template <typename T, typename U>
inline void smin(T &a, const U &b) {
  if (a > b) a = b;
}
template <typename T, typename U>
inline void smax(T &a, const U &b) {
  if (a < b) a = b;
}
template <class T>
inline void gn(T &first) {
  char c, sg = 0;
  while (c = getchar(), (c > '9' || c < '0') && c != '-')
    ;
  for ((c == '-' ? sg = 1, c = getchar() : 0), first = 0; c >= '0' && c <= '9';
       c = getchar())
    first = (first << 1) + (first << 3) + c - '0';
  if (sg) first = -first;
}
template <class T1, class T2>
inline void gn(T1 &x1, T2 &x2) {
  gn(x1), gn(x2);
}
template <class T1, class T2, class T3>
inline void gn(T1 &x1, T2 &x2, T3 &x3) {
  gn(x1, x2), gn(x3);
}
template <class T1, class T2, class T3, class T4>
inline void gn(T1 &x1, T2 &x2, T3 &x3, T4 &x4) {
  gn(x1, x2, x3), gn(x4);
}
template <class T1, class T2, class T3, class T4, class T5>
inline void gn(T1 &x1, T2 &x2, T3 &x3, T4 &x4, T5 &x5) {
  gn(x1, x2, x3, x4), gn(x5);
}
template <class T>
inline void print(T first) {
  if (first < 0) {
    putchar('-');
    return print(-first);
  }
  if (first < 10) {
    putchar('0' + first);
    return;
  }
  print(first / 10);
  putchar(first % 10 + '0');
}
template <class T>
inline void println(T first) {
  print(first);
  putchar('\n');
}
template <class T>
inline void printsp(T first) {
  print(first);
  putchar(' ');
}
template <class T1, class T2>
inline void print(T1 x1, T2 x2) {
  printsp(x1), println(x2);
}
template <class T1, class T2, class T3>
inline void print(T1 x1, T2 x2, T3 x3) {
  printsp(x1), printsp(x2), println(x3);
}
template <class T1, class T2, class T3, class T4>
inline void print(T1 x1, T2 x2, T3 x3, T4 x4) {
  printsp(x1), printsp(x2), printsp(x3), println(x4);
}
template <class T1, class T2, class T3, class T4, class T5>
inline void print(T1 x1, T2 x2, T3 x3, T4 x4, T5 x5) {
  printsp(x1), printsp(x2), printsp(x3), printsp(x4), println(x5);
}
int power(int a, int b, int m, int ans = 1) {
  for (; b; b >>= 1, a = 1LL * a * a % m)
    if (b & 1) ans = 1LL * ans * a % m;
  return ans;
}
vector<pair<int, long long> > dp[100010];
int w[100010];
int flag[100010];
int mnw[100010];
vector<int> adj[100010];
int ans[100010];
vector<int> st;
int n, L;
long long S;
int runs = 1;
int dfs(int u, int fa = 0) {
  for (int i = 0; i < adj[u].size(); i++) {
    int v = adj[u][i];
    if (v == fa) continue;
    dfs(v, u);
    ans[u] += ans[v];
  }
  runs++;
  for (int i = 0; i < adj[u].size(); i++) {
    int v = adj[u][i];
    if (v == fa) continue;
    for (int j = 0; j < dp[v].size(); j++) {
      pair<int, long long> Q = dp[v][j];
      if (Q.first != L and (long long) Q.second + w[u] <= S)
        st.push_back(Q.first + 1);
      else
        continue;
      if (flag[Q.first + 1] != runs)
        mnw[Q.first + 1] = Q.second + w[u], flag[Q.first + 1] = runs;
      else
        smin(mnw[Q.first + 1], Q.second + w[u]);
    }
  }
  for (int j = 0; j < st.size(); j++) {
    int first = st[j];
    dp[u].push_back(pair<int, long long>(first, mnw[first]));
  }
  if (st.size() == 0) dp[u].push_back(pair<int, long long>(1, w[u])), ans[u]++;
  st.clear();
  return 0;
}
int main() {
  gn(n, L, S);
  for (int i = 1; i <= n; i++) gn(w[i]);
  for (int i = 1; i <= n; i++)
    if (w[i] > S) {
      puts("-1");
      return 0;
    }
  for (int i = 2; i <= n; i++) {
    int first;
    gn(first);
    adj[first].push_back(i);
  }
  dfs(1);
  println(ans[1]);
  return 0;
}
