#include <bits/stdc++.h>
using namespace std;


typedef long long ll;
const int MAXN = 300005;

vector<int> graph[MAXN];
int n;

int fa[MAXN];
ll sz[MAXN];

int Fa(int x) {
	return fa[x] == x ? x : fa[x] = Fa(fa[x]);
}


void solve()
{
	ll ans = 0;
	cin >>n;
	for (int i=2, u; i<=n; i++) {
		cin >>u;
		graph[u].push_back(i);
		graph[i].push_back(u);
	}


	for (int i=1; i<=n; i++) {
		fa[i] = i;
		sz[i] = 1;
	}
	for (int u=n; u>=1; u--) {
		for (int v: graph[u]) if (v > u) {
			int fu = Fa(u);
			int fv = Fa(v);
			assert(fu != fv);
			ans += (sz[fu]-1) * sz[fv];
			fa[fv] = fu;
			sz[fu] += sz[fv];
			sz[fv] = 0;
		}
	}


	for (int i=1; i<=n; i++) {
		fa[i] = i;
		sz[i] = 1;
	}
	for (int u=1; u<=n; u++) {
		for (int v: graph[u]) if (v < u) {
			int fu = Fa(u);
			int fv = Fa(v);
			assert(fu != fv);
			ans += (sz[fu]-1) * sz[fv];
			fa[fv] = fu;
			sz[fu] += sz[fv];
			sz[fv] = 0;
		}
	}

	for (int i=1; i<=n; i++) {
		ans += 1ll * i * (n-i+1);
	}

	cout <<ans <<"\n";
}



int main()
{
	solve();
	return 0;
}