#include <iostream>
#include <vector>

using namespace std;
class BIT {
  const int size;
  vector<int> v;
public:
  BIT(int n) : size(n), v(n + 1) {}
  void add(int pos, int val) {
    ++pos;
    while (pos <= size) {
      v[pos] += val;
      pos += pos & (-pos);
    }
  }
  int query(int right) {
    int sum = 0;
    int pos = right;
    while (pos > 0) {
      sum += v[pos];
      pos -= pos & (-pos);
    }
    return sum;
  }
};

int n;
vector<int> G[200000];
BIT* bit;
long DFS(int from) {
  long sum = 0;
  sum += bit->query(from);
  bit->add(from, 1);
  for (int to : G[from]) {
    sum += DFS(to);
  }
  bit->add(from, -1);
  return sum;
}

int main() {
  cin >> n;
  bit = new BIT(n);
  for (int i = 1; i < n; ++i) {
    int p;
    cin >> p;
    G[p].push_back(i);
  }
  
  cout << DFS(0) << endl;
}