#include<bits/stdc++.h>
using namespace std;
#include <atcoder/modint>
using mint = atcoder::modint998244353;


int main(){
	int N;
	cin >> N;
	vector<int> pare(N);
	for (int i = 1; i < N; i++) cin >> pare[i], pare[i]--;
	assert(N <= 6);
	set<vector<int>> s;
	vector<int> B(N);
	auto f = [&](auto self, int var) -> void {
		if (var == N){
			vector<int> A(N);
			vector<set<int>> m(N);
			for (int i = N - 1; i >= 0; i--){
				m[i].insert(B[i]);
				if (i) for (auto x : m[i]) m[pare[i]].insert(x);
				while (m[i].count(A[i])) A[i]++;
			}
			s.insert(A);
			return;
		}
		for (int i = 0; i <= N; i++){
			B[var] = i;
			self(self, var + 1);
		}
	};
	f(f, 0);
	cout << s.size() << "\n";
}