#include <bits/stdc++.h>
using namespace std;
void dfs(vector<vector<int>> &c, vector<int> &L, vector<int> &R, int &t, int v = 0){
  L[v] = t;
  t++;
  for (int w : c[v]){
    dfs(c, L, R, t, w);
  }
  R[v] = t;
}
struct binary_indexed_tree{
  int N;
  vector<int> BIT;
  binary_indexed_tree(int N): N(N), BIT(N + 1, 0){
  }
  void add(int i){
    i++;
    while (i <= N){
      BIT[i]++;
      i += i & -i;
    }
  }
  int sum(int i){
    int ans = 0;
    while (i > 0){
      ans += BIT[i];
      i -= i & -i;
    }
    return ans;
  }
  int sum(int L, int R){
    return sum(R) - sum(L);
  }
};
int main(){
  int N;
  cin >> N;
  vector<int> A(N, -1);
  for (int i = 1; i < N; i++){
    cin >> A[i];
  }
  vector<vector<int>> c(N);
  for (int i = 1; i < N; i++){
    c[A[i]].push_back(i);
  }
  vector<int> L(N), R(N);
  int t = 0;
  dfs(c, L, R, t);
  binary_indexed_tree BIT(N);
  long long ans = 0;
  for (int i = N - 1; i >= 0; i--){
    ans += BIT.sum(L[i], R[i]);
    BIT.add(L[i]);
  }
  cout << ans << endl;
}