class Bit:
    def __init__(self, n):
        self.size = n
        self.tree = [0] * (n + 1)
 
    def _add(self, i, x):
        while i <= self.size:
            self.tree[i] += x
            i += i & -i
            
    def _sum(self, i):
        s = 0
        while i > 0:
            s += self.tree[i]
            i -= i & -i
        return s
        
n=int(input())
rin=[[] for i in range(n)]
a=list(map(int,input().split()))

for i in range(1,n):
    rin[a[i-1]].append(i)
    rin[i].append(a[i-1])

bit=Bit(n+2)

import sys
sys.setrecursionlimit(10**6)
kukan = [[0,0] for i in range(n)]
ind=1
def  cal(x,pre):
    global ind
    kukan[x][0] = ind
    if len(rin[x]) == 1 and x!= pre:
        kukan[x][1] = ind
        ind += 1
        return
    ind += 1
    for i in rin[x]:
        if i != pre:
            cal(i,x)
    
    kukan[x][1] = ind-1

cal(0,0)
ans = 0
for x in range(n-1,-1,-1):
    l,r=kukan[x][0],kukan[x][1]
    ans += bit._sum(r) - bit._sum(l-1)
    bit._add(l,1)


print(ans)