#include<iostream>
#include<vector>
#include<string>
#include<cmath>
#include<algorithm>
#include<functional>
#include<numeric>
#include<queue>
#include<stack>
#include<map>
#include<unordered_map>
#include<set>
#include<bitset>
#include<random>

#pragma region
using namespace std;
#define FOR(i,r,n) for(ll i = (ll)(r); i < (ll)(n); i++)
#define rep(i,n) FOR(i,0LL,n)
#define RFOR(i,r,n) for(ll i=(ll)(n-1);i>=r;i--)
#define rrep(i,n) RFOR(i,0LL,n)
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define COUNT(a,y,x) upper_bound(all(a), y) - lower_bound(all(a), x)
#define UNIQUE(a) sort(all(a)); a.erase(unique(all(a)), a.end())
#define pb push_back
#define endl '\n'
typedef long long int ll;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef pair<ll, ll> pll;
typedef vector<pll> vpll;
typedef vector<string> vs;
typedef map<ll, ll> MAP;
const ll inf = 2222222222222222222LL;
const ll mod = 1000000007LL;

ll n = 0, m = 0, ans = 0, tmp = 0, ma = -inf, mi = inf;
string s;
bool ok;
ll dx[9] = { 0,1,-1,0,0,1,1,-1,-1 }, dy[9] = { 0,0,0,1,-1,1,-1,1,-1 };
#pragma endregion
#define MAX 222222


struct BinaryIndexed {
  ll num;
  vll bit;

  BinaryIndexed(ll x = MAX) {
    num = x;
    bit.resize(x + 1, 0);
  }

  ll sum(ll i) {
    ll ret = 0;
    while (i > 0) {
      ret += bit[i];
      i -= i & -i;
    }
    return ret;
  }

  void add(ll i, ll x) {
    if (i == 0) cout << "access 0 index" << endl;
    while (i <= num) {
      bit[i] += x;
      i += i & -i;
    }
  }
};

BinaryIndexed b(MAX);
vll edge[MAX];

void dfs(ll cur) {

  if (cur != 0) {
    ans += b.sum(cur) + 1;
    b.add(cur, 1);
  }
  rep(i, edge[cur].size()) dfs(edge[cur][i]);
  if (cur != 0) b.add(cur, -1);
}

int main(void) {
  ios::sync_with_stdio(false); cin.tie(0);


  cin >> n;
  FOR(i, 1, n) {
    cin >> tmp;
    edge[tmp].pb(i);
  }
  dfs(0);
  cout << ans << endl;


  return 0;
}