#include <bits/stdc++.h>

#define fst(t) std::get<0>(t)
#define snd(t) std::get<1>(t)
#define thd(t) std::get<2>(t)
#define unless(p) if(!(p))
#define until(p) while(!(p))

using ll = long long;
using P = std::tuple<int,int>;

const int dx[8] = {-1, 1, 0, 0, -1, -1, 1, 1}, dy[8] = {0, 0, -1, 1, -1, 1, -1, 1};

struct FenwickTree{
    int numNode;
    std::vector<int> data;
    
    FenwickTree(int n) : numNode(n), data(n + 1, 0) {}

    void add(int k, int v){
        k += 1;
        
        while(k <= numNode){
            data[k] += v;
            k += k & -k;
        }
    }

    int sum(int k){
        k += 1;

        int res = 0;
        while(k > 0){
            res += data[k];
            k -= k & -k;
        }

        return res;
    }
};

int N;
std::vector<int> G[200100];
ll cnt;
FenwickTree ft(200100);

void dfs(int v){
    cnt += ft.sum(v);

    ft.add(v, +1);

    for(int w : G[v]){
        dfs(w);
    }

    ft.add(v, -1);
}

int main(){
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    std::cin >> N;

    for(int i=1;i<=N-1;++i){
        int p;
        std::cin >> p;

        G[p].emplace_back(i);
    }

    dfs(0);

    std::cout << cnt << std::endl;
}