import sequtils,strutils
type
    binaryIndexTree[I:static[int]] = array[I + 1,int] 

proc add(BIT :var binaryIndexTree,i : int, a : int)=
    var index = i
    while BIT[0] >= index:
        BIT[index] += a
        index += ((index xor (index - 1)) and index)

proc sum(BIT : binaryIndexTree, i : int):int =
    var index = i
    while index > 0:
        result += BIT[index]
        index = (index and (index - 1))


var
    BIT : binaryIndexTree[200010]
BIT[0] = 200010

var
    N = stdin.readline.parseInt
    A = stdin.readline.split.map(parseInt)
    B = newSeqWith(N + 1,newSeq[int](0))
    ans = 0
    
for i,a in A:
    B[a + 1].add(i + 2)


proc dfs(i : int) =
    ans += BIT.sum(i)
    BIT.add(i, 1)
    for p in B[i]:
        dfs(p)
    BIT.add(i, -1)
dfs(1)
echo ans