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


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

    def add(self, p, x):
        assert 0 <= p < self.n
        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 < self.n
        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 < self.n
        s = self.sum(r)
        if l > 0:
            s -= self.sum(l-1)
        return s


class EulerTourVertex:
    def __init__(self, n, adj, root=0):
        vs = []  # 頂点 (訪問順)
        v_in = [0] * n   # 頂点の最初に通った時刻
        v_out = [0] * n  # 頂点の最後に通った時刻

        def dfs(v, par):
            vs.append(v)
            v_in[v] = len(vs)-1
            for to in adj[v]:
                if to == par: continue
                dfs(to, v)
                vs.append(v)

            v_out[v] = len(vs)-1

        dfs(root, -1)
        self.vs = vs
        self.v_in = v_in
        self.v_out = v_out


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)

et = EulerTourVertex(N, adj, root=0)
ft = FenwickTree(len(et.vs) + 10)
ans = 0
for i in reversed(range(N)):  # 頂点番号の大きい順
    # 部分木に、頂点 i よりも大きい頂点の個数をカウント
    ans += ft.rangesum(et.v_in[i], et.v_out[i])
    ft.add(et.v_in[i], 1)

print(ans)