#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>

using namespace std;

typedef long long ll;

#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(ll i=(a);i<(b);++i)
#define per(i,a,b) for(ll i=b-1LL;i>=(a);--i)
#define clr(a, b) memset((a), (b) ,sizeof(a))
#define ctos(c) string(1,c)
#define print(x) cout<<#x<<" = "<<x<<endl;

#define MOD 1000000007

#define N_MAX 400100

struct bit{
  long long dat[N_MAX + 1];

  void init(){
    for(int i = 0; i < N_MAX; i++){
      dat[i] = 0;
    }
  }

  long long sum(int i){
    long long s = 0;
    while(i > 0){
      s += dat[i];
      i -= i & -i;
    }
    return s;
  }

  void add(int i, long long x){
    while(i <= N_MAX){
      dat[i] += x;
      i += i & -i;
    }
  }
}bit1;

ll index1;
ll dl[200100];
ll dr[200100];
vector<vector<ll> > vv;

void f(ll p){
  dl[p] = index1;
  index1++;
  rep(i,0,vv[p].sz){
    f(vv[p][i]);
  }
  dr[p] = index1;
  index1++;
}

int main() {
  ll n;
  cin>>n;
  bit1.init();
  vector<vector<ll> > vv_(n,vector<ll>());
  vv = vv_;
  rep(i,1,n){
    ll a;
    cin>>a;
    vv[a].pb(i);
  }
  index1 = 1;
  f(0);
  ll ans = 0;
  per(i,0,n){
    ans += bit1.sum(dr[i])-bit1.sum(dl[i]);
    bit1.add(dl[i],1);
  }
  cout << ans << endl;
  return 0;
}