#include <limits>
#include <iostream>
#include <algorithm>
#include <iomanip>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>

static const int MOD = 1000000007;
using ll = long long;
using u32 = uint32_t;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max()/32*15+208;

template<class T>
class BIT {
    vector<T> bit;
public:
    BIT(int n): bit(vector<T>(n+1, 0)){}

    T sum(int k){
        T ret = 0;
        for (++k; k > 0; k -= (k & -k)) ret += bit[k];
        return ret;
    }

    void add(int k, T x){
        for (++k; k < bit.size(); k  += (k & -k)) bit[k] += x;
    }
};

class euler_tour {
    void dfs_sz(int v){
        for (auto &&u : G[v]) {
            if(u == par[v]) continue;
            par[u] = v; dep[u] = dep[v] + 1;
            dfs_sz(u);
            sub_size[v] += sub_size[u];
            if(sub_size[u] > sub_size[G[v][0]]) swap(u, G[v][0]);
        }
    }

    void dfs_hld(int v, int c, int &pos){
        id[v] = pos++;
        id_inv[id[v]]= v;
        tree_id[v] = c;
        for (auto &&u : G[v]) {
            if(u == par[v]) continue;
            head[u] = (u == G[v][0] ? head[v] : u);
            dfs_hld(u, c, pos);
        }
    }

public:
    int n;
    vector<vector<int>> G;
    vector<int> par, dep, sub_size, id, id_inv, tree_id, head;
    explicit euler_tour(int n) : n(n), G(n), par(n), dep(n), sub_size(n, 1),
                                 id(n), id_inv(n), tree_id(n), head(n){}
    explicit euler_tour(vector<vector<int>> &G) :
            G(G), n(n), par(n), dep(n) , sub_size(n), id(n), id_inv(n), tree_id(n), head(n) {}

    void add_edge(int u, int v){
        G[u].emplace_back(v);
        G[v].emplace_back(u);
    }

    void build(vector<int> roots = {0}){
        int c = 0, pos = 0;
        for (auto &&i : roots) {
            dfs_sz(i);
            head[i] = i;
            dfs_hld(i, c++, pos);
        }
    }
};

int main() {
    int n;
    cin >> n;
    euler_tour G(n);
    for (int i = 1; i < n; ++i) {
        int x; scanf("%d", &x);
        G.add_edge(x, i);
    }
    G.build();
    ll ans = 0;
    BIT<ll> b(n);
    for (int j = n - 1; j >= 0; --j) {
        ans += b.sum(G.id[j]+G.sub_size[j]-1)-b.sum(G.id[j]);
        b.add(G.id[j], 1);
    }
    cout << ans << "\n";
    return 0;
}