#include <bits/stdc++.h>
using namespace std;

struct EulerTour{
    // オイラーツアー
    vector<int> tour;
    // 各頂点番号に対する、tourの最左/最右の位置
    vector<int> L, R;

    EulerTour(){}
    EulerTour(int N, vector<int> G[], int root=0){ initialize(N, G, root); }

    void dfs(int i, int p, vector<int> G[]){
        L[i] = tour.size();
        tour.push_back(i);
        for(int j : G[i]) if(j != p){
            dfs(j, i, G);
            tour.push_back(i);
        }
        R[i] = tour.size()-1;
    }
    void initialize(int N, vector<int> G[], int root){
        L.resize(N);
        R.resize(N);
        dfs(root, -1, G);
    }
};

template<typename T>
struct BIT {
    int n;
    vector<T> dat;

    BIT(int n=0){
        initialize(n);
    }

    void initialize(int nin){
        n = nin;
        dat.resize(n, 0);
    }

    T sum(int i){
        T s = 0;
        while(i >= 0){
            s += dat[i];
            i = (i & (i+1)) - 1;
        }
        return s;
    }

    T sum_between(int i, int j){
        return sum(j) - sum(i-1);
    }

    void plus(int i, T x){
        while(i < n){
            dat[i] += x;
            i |= i+1;
        }
    }

    // a[0]+...+a[ret] >= x
    int lower_bound(T x){
        int ret = -1;
        int k = 1;
        while(2*k <= n) k <<= 1;
        for( ;k>0; k>>=1){
            if(ret+k < n && dat[ret+k] < x){
                x -= dat[ret+k];
                ret += k;
            }
        }
        return ret + 1;
    }
};

vector<int> child[200000];

int main(){
    int N;
    cin >> N;
    for(int i=1; i<N; i++){
        int a;
        cin >> a;
        child[a].push_back(i);
    }
    
    EulerTour et(N, child, 0);
    int len = et.tour.size();
    BIT<int64_t> bit(len);

    int64_t ans = 0;
    for(int i=N-1; i>=0; i--){
        ans += bit.sum_between(et.L[i], et.R[i]);
        bit.plus(et.L[i], 1);
    }
    cout << ans << endl;
    return 0;
}