#ifndef LOCAL
#define NDEBUG
#endif

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

namespace iefnah {

template <int MOD_> struct modnum {
	static constexpr int MOD = MOD_;
	static_assert(MOD_ > 0, "MOD must be positive");

private:
	using ll = long long;

	int v;

	static int minv(int a, int m) {
		a %= m;
		assert(a);
		return a == 1 ? 1 : int(m - ll(minv(m, a)) * ll(m) / a);
	}

public:

	modnum() : v(0) {}
	modnum(ll v_) : v(int(v_ % MOD)) { if (v < 0) v += MOD; }
	explicit operator int() const { return v; }
	friend std::ostream& operator << (std::ostream& out, const modnum& n) { return out << int(n); }
	friend std::istream& operator >> (std::istream& in, modnum& n) { ll v_; in >> v_; n = modnum(v_); return in; }

	friend bool operator == (const modnum& a, const modnum& b) { return a.v == b.v; }
	friend bool operator != (const modnum& a, const modnum& b) { return a.v != b.v; }

	modnum inv() const {
		modnum res;
		res.v = minv(v, MOD);
		return res;
	}
	friend modnum inv(const modnum& m) { return m.inv(); }
	modnum neg() const {
		modnum res;
		res.v = v ? MOD-v : 0;
		return res;
	}
	friend modnum neg(const modnum& m) { return m.neg(); }

	modnum operator- () const {
		return neg();
	}
	modnum operator+ () const {
		return modnum(*this);
	}

	modnum& operator ++ () {
		v ++;
		if (v == MOD) v = 0;
		return *this;
	}
	modnum& operator -- () {
		if (v == 0) v = MOD;
		v --;
		return *this;
	}
	modnum& operator += (const modnum& o) {
		v += o.v;
		if (v >= MOD) v -= MOD;
		return *this;
	}
	modnum& operator -= (const modnum& o) {
		v -= o.v;
		if (v < 0) v += MOD;
		return *this;
	}
	modnum& operator *= (const modnum& o) {
		v = int(ll(v) * ll(o.v) % MOD);
		return *this;
	}
	modnum& operator /= (const modnum& o) {
		return *this *= o.inv();
	}

	friend modnum operator ++ (modnum& a, int) { modnum r = a; ++a; return r; }
	friend modnum operator -- (modnum& a, int) { modnum r = a; --a; return r; }
	friend modnum operator + (const modnum& a, const modnum& b) { return modnum(a) += b; }
	friend modnum operator - (const modnum& a, const modnum& b) { return modnum(a) -= b; }
	friend modnum operator * (const modnum& a, const modnum& b) { return modnum(a) *= b; }
	friend modnum operator / (const modnum& a, const modnum& b) { return modnum(a) /= b; }
};

template <typename T> T pow(T a, long long b) {
	assert(b >= 0);
	T r = 1; while (b) { if (b & 1) r *= a; b >>= 1; a *= a; } return r;
}

using num = modnum<int(1e9)+7>;

class RestrictedLeaves {

public:

	int count(vector<int> parent) {
		int N = int(parent.size());
		vector<vector<int>> adj(N);
		for (int i = 1; i < N; i++) {
			assert(parent[i] < i);
			adj[parent[i]].push_back(i);
		}

		vector<array<num, 8>> dp(N); // left/right/self
		for (int cur = N-1; cur >= 0; cur--) {
			dp[cur].fill(0);
			if (adj[cur].empty()) {
				dp[cur][0] = dp[cur][7] = 1;
				continue;
			}

			sort(adj[cur].begin(), adj[cur].end());
			for (int m = 0; m < 8; m++) {
				bool isFirst = true;
				array<num, 2> tmp = {1, 0};

				for (int nxt : adj[cur]) {
					array<num, 2> ntmp = {};
					for (int t = 0; t < 8; t++) {
						if ((m & 4) && (t & 4)) continue;
						if (isFirst && (m & 1) != (t & 1)) continue;
						for (int a = 0; a < 2; a++) {
							if (a && (t & 1)) continue;
							ntmp[bool(t & 2)] += tmp[a] * dp[nxt][t];
						}
					}
					tmp = std::move(ntmp);

					isFirst = false;
				}

				dp[cur][m] = tmp[bool(m & 2)];
			}
		}

		num ans = 0;
		for (int m = 0; m < 8; m++) {
			if (bool(m & 1) && bool(m & 2)) continue;
			ans += dp[0][m];
		}
		return int(ans);
	}
};

}  // namespace iefnah

using iefnah::RestrictedLeaves;