#pragma GCC optimize ("O3")
#include "bits/stdc++.h"

using namespace std;
using ll = long long int;

#define debugos cout
#define debug(v) {printf("L%d %s > ",__LINE__,#v);debugos<<(v)<<endl;}
#define debugv(v) {printf("L%d %s > ",__LINE__,#v);for(auto e:(v)){debugos<<e<<" ";}debugos<<endl;}
#define debuga(m,w) {printf("L%d %s > ",__LINE__,#m);for(int x=0;x<(w);x++){debugos<<(m)[x]<<" ";}debugos<<endl;}
#define debugaa(m,h,w) {printf("L%d %s >\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){debugos<<(m)[y][x]<<" ";}debugos<<endl;}}
#define ALL(v) (v).begin(),(v).end()
#define repeat(cnt,l) for(auto cnt=decltype(l)();(cnt)<(l);++(cnt))
#define rrepeat(cnt,l) for(auto cnt=(l)-1;0<=(cnt);--(cnt))
#define iterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);++(cnt))
#define diterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);--(cnt))
const ll MD = 1000000007ll; const long double PI = 3.1415926535897932384626433832795L;
inline void assert_call(bool assertion, function<void()> f) { if (!assertion) { cerr << "assertion fault:" << endl; f(); abort(); } }
template<typename T1, typename T2> inline ostream& operator <<(ostream &o, const pair<T1, T2> p) { o << '(' << p.first << ':' << p.second << ')'; return o; }
template<typename Vec> inline ostream& _ostream_vecprint(ostream& os, const Vec& a) {
    os << '['; for (const auto& e : a) os << ' ' << e << ' '; os << ']'; return os; }
template<typename T> inline ostream& operator<<(ostream& o, const vector<T>& v) { return _ostream_vecprint(o, v); }
template<typename T, size_t S> inline ostream& operator<<(ostream& o, const array<T, S>& v) { return _ostream_vecprint(o, v); }
template<typename T> inline T& chmax(T& to, const T& val) { return to = max(to, val); }
template<typename T> inline T& chmin(T& to, const T& val) { return to = min(to, val); }
void bye(string s, int code = 0) { cout << s << endl; exit(code); }
mt19937_64 randdev(8901016);
template<typename T, typename Random = decltype(randdev), typename enable_if<is_integral<T>::value>::type* = nullptr>
inline T rand(T l, T h, Random& rand = randdev) { return uniform_int_distribution<T>(l, h)(rand); }
template<typename T, typename Random = decltype(randdev), typename enable_if<is_floating_point<T>::value>::type* = nullptr>
inline T rand(T l, T h, Random& rand = randdev) { return uniform_real_distribution<T>(l, h)(rand); }

#if defined(_WIN32) || defined(_WIN64)
#define getchar_unlocked _getchar_nolock
#define putchar_unlocked _putchar_nolock
#elif defined(__GNUC__)
#else
#define getchar_unlocked getchar
#define putchar_unlocked putchar
#endif
namespace {
#define isvisiblechar(c) (0x21<=(c)&&(c)<=0x7E)
    class MaiScanner {
    public:
        template<typename T> void input_integer(T& var) noexcept {
            var = 0; T sign = 1;
            int cc = getchar_unlocked();
            for (; cc<'0' || '9'<cc; cc = getchar_unlocked())
                if (cc == '-') sign = -1;
            for (; '0' <= cc && cc <= '9'; cc = getchar_unlocked())
                var = (var << 3) + (var << 1) + cc - '0';
            var = var * sign;
        }
        inline int c() noexcept { return getchar_unlocked(); }
        inline MaiScanner& operator>>(int& var) noexcept { input_integer<int>(var); return *this; }
        inline MaiScanner& operator>>(long long& var) noexcept { input_integer<long long>(var); return *this; }
        inline MaiScanner& operator>>(string& var) {
            int cc = getchar_unlocked();
            for (; !isvisiblechar(cc); cc = getchar_unlocked());
            for (; isvisiblechar(cc); cc = getchar_unlocked())
                var.push_back(cc);
            return *this;
        }
        template<typename IT> inline void in(IT begin, IT end) { for (auto it = begin; it != end; ++it) *this >> *it; }
    };
    class MaiPrinter {
    public:
        template<typename T>
        void output_integer(T var) noexcept {
            if (var == 0) { putchar_unlocked('0'); return; }
            if (var < 0)
                putchar_unlocked('-'),
                var = -var;
            char stack[32]; int stack_p = 0;
            while (var)
                stack[stack_p++] = '0' + (var % 10),
                var /= 10;
            while (stack_p)
                putchar_unlocked(stack[--stack_p]);
        }
        inline MaiPrinter& operator<<(char c) noexcept { putchar_unlocked(c); return *this; }
        inline MaiPrinter& operator<<(int var) noexcept { output_integer<int>(var); return *this; }
        inline MaiPrinter& operator<<(long long var) noexcept { output_integer<long long>(var); return *this; }
        inline MaiPrinter& operator<<(char* str_p) noexcept { while (*str_p) putchar_unlocked(*(str_p++)); return *this; }
        inline MaiPrinter& operator<<(const string& str) {
            const char* p = str.c_str();
            const char* l = p + str.size();
            while (p < l) putchar_unlocked(*p++);
            return *this;
        }
        template<typename IT> void join(IT begin, IT end, char sep = ' ') { for (bool b = 0; begin != end; ++begin, b = 1) b ? *this << sep << *begin : *this <<* begin; }
    };
}
MaiScanner scanner;
MaiPrinter printer;


template<typename T = ll>
class Bitree {
    const int size_;
    vector<T> data_;
    static int nlz(uint32_t x) {
        union {
            uint32_t i; float f;
        } data;
        data.f = (float)x + 0.5;
        return 158 - (data.i >> 23);
    }
public:
    Bitree(int size_) :size_(size_), data_(size_+1) {}

    // 1..rの範囲の値の和を求める．
    T sum(int r) const {
        T s = 0;
        while (r) {
            s += data_[r];
            r -= r&-r; //  r&-r と書くことで最下のビットを得る
        }
        return s;
    }
    // l..rの範囲の値の和を求める
    inline T sum(int l, int r) const { return sum(r) - sum(l-1); }
    // i番目の値を求める(1index)
    T get(int i) const {
        int j = i - 1;
        T s = 0;
        while (i != j) {
            s += data_[i] - data_[j];
            i -= i&-i; j -= j&-j;
        }
        return s;
    }
    // idxの要素の値をval増やす
    void add(int idx, T val) {
        while (idx <= size_) {
            data_[idx] += val;
            idx += idx&-idx;
        }
    }
    // sum(i)がvalを超える最初のiを返す
    // get(j)<0となるjが存在すると正しく動作しない
    int upper_bound(T val) const {
        int li = 1 << (31 - nlz(size_));
        int p = 0; T d = 0;
        while (li && p < size_) {
            T k = data_[p | li];
            if (!(val < d + k))
                p |= li,
                d += k;
            li >>= 1;
        }
        if (p > size_) p = size_;
        return p+1;
    }
    // sum(i)がval以上である最初のiを返す
    // get(j)<0となるjが存在すると正しく動作しない
    int lower_bound(T val) const {
        int li = 1 << (31 - nlz(size_));
        int p = 0; T d = 0;
        while (li && p < size_) {
            T k = data_[p | li];
            if (d + k < val)
                p |= li, d += k;
            li >>= 1;
        }
        if (p > size_) p = size_;
        return p+1;
    }
};
int N;
int P[200010];
vector<int> V[200010];

ll total = 0;

void dfs(int idx, Bitree<int>& parents){
    total += parents.sum(idx);
    parents.add(idx+1, 1);
    for (int v : V[idx])
        dfs(v, parents);
    parents.add(idx+1, -1);
}

int main(){
    scanner >> N;
    scanner.in(P, P+N-1);
    repeat(i, N-1)
        V[P[i]].push_back(i+1);
    Bitree<int> bit(N);
    dfs(0, bit);
    printer << total << '\n';
    return 0;
}