class BinaryIndexedTree(object):
    __slots__ = ["tree"]

    def __init__(self, size: int):
        self.tree = [0]*(size+1)

    def add(self, index: int, value: int):
        tree = self.tree

        while index < len(tree):
            tree[index] += value
            index += index & -index

    def sum(self, index: int):
        tree, result = self.tree, 0

        while index:
            result += tree[index]
            index -= index & -index

        return result


def euler_tour(tree):
    import sys
    sys.setrecursionlimit(10**7)
    edges = [[] for _ in [0]*(len(tree)+1)]
    for origin, destination in enumerate(tree, start=1):
        edges[destination].append(origin)

    subtree_range = [[0, 0] for _ in [0]*(len(tree)+1)]

    def rec(v, index):
        subtree_range[v][0] = index
        for destination in edges[v]:
            index = rec(destination, index+1)
        subtree_range[v][1] = index

        return index + 1

    rec(0, 1)
    return subtree_range


if __name__ == "__main__":
    N = int(input())
    tree = list(map(int, input().split()))
    subtree_range = euler_tour(tree)
    bit = BinaryIndexedTree(2*N-1)
    ans = 0

    for start, end in subtree_range[::-1]:
        ans += bit.sum(end) - bit.sum(start-1)
        bit.add(start, 1)

    print(ans)