from collections import defaultdict
import sys
sys.setrecursionlimit(10 ** 6)


class FenwickTree:
    def __init__(self, n):
        self.data = [0] * (n + 10)

    def add(self, p, x):
        assert 0 <= p
        p += 1
        while p < len(self.data):
            self.data[p] += x
            p += p & -p

    def sum(self, p):
        """区間 [0, p] の和"""
        assert 0 <= p
        p += 1
        s = 0
        while p > 0:
            s += self.data[p]
            p -= p & -p
        return s

    def rangesum(self, l, r):
        """区間 [l, r] の和"""
        assert 0 <= l <= r
        s = self.sum(r)
        if l > 0:
            s -= self.sum(l-1)
        return s


class EulerTour:
    def __init__(self, n: int, root: int, adj):
        tour = []  # オイラーツアー
        lt = [0] * n  # 各頂点番号に対する tour の最左/最右の位置
        rt = [0] * n

        def dfs(v, prev):
            lt[v] = len(tour)
            tour.append(v)
            for to in adj[v]:
                if to == prev: continue
                dfs(to, v)
                tour.append(v)
            rt[v] = len(tour) - 1

        dfs(root, -1)
        self.tour = tour
        self.lt = lt
        self.rt = rt


N = int(input())
A = list(map(int, input().split()))

adj = defaultdict(list)
for i in range(N-1):
    par = A[i]
    adj[par].append(i+1)

ans = 0
et = EulerTour(N, 0, adj)
ft = FenwickTree(len(et.tour) + 10)
for i in range(N-1, -1, -1):
    ans += ft.rangesum(et.lt[i], et.rt[i])
    ft.add(et.lt[i], 1)

print(ans)