using System;
using System.Linq;
using System.Collections.Generic;
using System.Diagnostics;
using Debug = System.Diagnostics.Trace;
using SB = System.Text.StringBuilder;
using System.Numerics;
using static System.Math;
using static System.Console;
namespace Program
{
public class Solver
{
Random rnd = new Random();
public void Solve()
{
var n = ri;
var G = Enumerate(n, x => new List<int>());
for (int i = 1; i < n; i++)
{
var p = ri - 1;
G[p].Add(i);
}
Func<int, int, KeyValuePair<int, long[,]>> dfs = null;
dfs = (prev, cur) =>
{
var size = 1;
//dp[sz,deg] = sz 個の連結成分からなり、次数が deg
var ret = new long[2, 3];
ret[1, 2] = 1;
foreach (var t in G[cur])
{
var sz = size;
var res = dfs(cur, t);
size += res.Key;
ret = merge(new int[] { sz, res.Key }, ret, res.Value);
}
return new KeyValuePair<int, long[,]>(size, ret);
};
var dp = dfs(-1, 0).Value;
long ans = 0;
var fact = new long[n + 1];
fact[0] = 1;
for (int i = 0; i < n; i++)
fact[i + 1] = fact[i] * (i + 1) % MOD;
for (int i = 0; i <= n; i++)
for (int d = 0; d <= 2; d++)
{
//Console.WriteLine($"{i} {d} {dp[i, d]}");
var v = dp[i, d] * fact[i] % MOD;
if (d != 2) v *= 2;
if ((n - i) % 2 == 0) ans += v;
else ans -= v;
ans %= MOD;
}
Console.WriteLine((ans + MOD) % MOD);
}
const long MOD = (long)1e9 + 7;
//merge b to a
long[,] merge(int[] sz, long[,] a, long[,] b)
{
var ret = new long[sz[0] + sz[1] + 1, 3];
for (int i = 0; i <= sz[0]; i++)
for (int j = 0; j <= sz[1]; j++)
for (int d = 0; d <= 2; d++)
for (int e = 0; e <= 2; e++)
{
var add = a[i, d] * b[j, e] % MOD;
if (add == 0) continue;
//Console.WriteLine($"{i} {j} {d} {e} {u} {v} {a[i, d, u]} {b[j, e, v]}");
update(ref ret[i + j, d], add * (e == 2 ? 1 : 2));
if (d != 0 && e != 0)
{
//Console.WriteLine($"@ i:{i} j:{j} d:{d} e:{e} u:{u} v:{v} a:{a[i, d, u]} b:{b[j, e, v]}");
update(ref ret[i + j - 1, d - 1], add);
}
}
return ret;
}
void update(ref long u, long v)
{
u += v;
u %= MOD;
}
const long INF = 1L << 60;
static int[] dx = { -1, 0, 1, 0 };
static int[] dy = { 0, 1, 0, -1 };
int ri { get { return sc.Integer(); } }
long rl { get { return sc.Long(); } }
double rd { get { return sc.Double(); } }
string rs { get { return sc.Scan(); } }
public IO.StreamScanner sc = new IO.StreamScanner(Console.OpenStandardInput());
static T[] Enumerate<T>(int n, Func<int, T> f)
{
var a = new T[n];
for (int i = 0; i < n; ++i) a[i] = f(i);
return a;
}
static public void Swap<T>(ref T a, ref T b) { var tmp = a; a = b; b = tmp; }
}
}
#region main
static class Ex
{
static public string AsString(this IEnumerable<char> ie) { return new string(ie.ToArray()); }
static public string AsJoinedString<T>(this IEnumerable<T> ie, string st = " ")
{
return string.Join(st, ie);
}
static public void Main()
{
Console.SetOut(new Program.IO.Printer(Console.OpenStandardOutput()) { AutoFlush = false });
var solver = new Program.Solver();
solver.Solve();
Console.Out.Flush();
}
}
#endregion
#region Ex
namespace Program.IO
{
using System.IO;
using System.Text;
using System.Globalization;
public class Printer : StreamWriter
{
public override IFormatProvider FormatProvider { get { return CultureInfo.InvariantCulture; } }
public Printer(Stream stream) : base(stream, new UTF8Encoding(false, true)) { }
}
public class StreamScanner
{
public StreamScanner(Stream stream) { str = stream; }
public readonly Stream str;
private readonly byte[] buf = new byte[1024];
private int len, ptr;
public bool isEof = false;
public bool IsEndOfStream { get { return isEof; } }
private byte read()
{
if (isEof) return 0;
if (ptr >= len)
{
ptr = 0;
if ((len = str.Read(buf, 0, 1024)) <= 0)
{
isEof = true;
return 0;
}
}
return buf[ptr++];
}
public char Char()
{
byte b = 0;
do b = read(); while ((b < 33 || 126 < b) && !isEof);
return (char)b;
}
public string Scan()
{
var sb = new StringBuilder();
for (var b = Char(); b >= 33 && b <= 126; b = (char)read()) sb.Append(b);
return sb.ToString();
}
public string ScanLine()
{
var sb = new StringBuilder();
for (var b = Char(); b != '\n' && b != 0; b = (char)read()) if (b != '\r') sb.Append(b);
return sb.ToString();
}
public long Long() { return isEof ? long.MinValue : long.Parse(Scan()); }
public int Integer() { return isEof ? int.MinValue : int.Parse(Scan()); }
public double Double() { return isEof ? double.NaN : double.Parse(Scan(), CultureInfo.InvariantCulture); }
}
}
#endregion