bool M1;
#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/hash_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ll long long
#define ull unsigned long long
#define LL __int128
#define db double
#define LD long double
#define Pii pair<int,int>
#define Pll pair<ll,ll>
#define Pull pair<ull,ull>
#define Pdb pair<db,db>
#define fir first
#define sec second
#define vec vector<int>
#define pb push_back
#define qlr cerr<<"qlr\n"
#define dyh cerr<<"dyh\n"
#define pc(x) __builtin_popcount(x)
#define uni(x,y) uniform_int_distribution<int>(x,y)(rng)
#define unl(x,y) uniform_int_distribution<ll>(x,y)(rng)
#define unr(x,y) uniform_real_distribution<double>(x,y)(rng)
#define F(i,a,b) for(int i=a,i##end=b;i<=i##end;i++)
#define UF(i,a,b) for(int i=a,i##end=b;i>=i##end;i--)
#define look_memory cerr<<'\n'<<abs(&M1-&M2)/1024.0/1024<<'\n'
#define look_time cerr<<'\n'<<clock()*1.0/CLOCKS_PER_SEC<<'\n'
mt19937 rng(time(0)^(*new int));
const ll INF=0x3f3f3f3f3f3f3f3f;
const int Mod=998244353;
template<typename T>
inline void inc(T &a,T b){
	if(b<0) b+=Mod;
	a+=b;
	if(a>=Mod) a-=Mod;
}
template<typename T>
inline void dec(T &a,T b){
	if(b<0) b+=Mod;
	a-=b;
	if(a<0) a+=Mod;
}
template<typename T>
inline void muc(T &a,T b){
	a=a*b%Mod;
}
template<typename T>
inline bool chkmin(T &a,T b){
	if(a<=b) return false;
	a=b;
	return true;
}
template<typename T>
inline bool chkmax(T &a,T b){
	if(a>=b) return false;
	a=b;
	return true;
}
int n;
ll ans;
int dep[100010];
ll fac[100010],inv[100010],ifac[100010];
ll f[100010][40],tf[40];
vec e[100010];
void dfs(int u,int fa){
	dep[u]=dep[fa]+1;
	f[u][0]=1;
	for(auto v:e[u]){
		if(v==fa) continue;
		dfs(v,u);
		memset(tf,0,sizeof(tf));
		UF(i,dep[u],0){
			F(j,0,dep[u]-i) tf[i+j]=(tf[i+j]+f[u][i]*f[v][j])%Mod;
		}
		memcpy(f[u],tf,sizeof(f[u]));
	}
	UF(i,dep[u],1){
		F(j,0,i-1) f[u][i]=(f[u][i]+f[u][j]*ifac[i-j])%Mod;
	}
	F(i,0,dep[u]) f[u][i]=f[u][i+1];
}
void init(){
	#define N 100000
	fac[0]=1;
	F(i,1,N) fac[i]=fac[i-1]*i%Mod;
	inv[1]=1;
	F(i,2,N) inv[i]=(Mod-Mod/i)*inv[Mod%i]%Mod;
	ifac[0]=1;
	F(i,1,N) ifac[i]=ifac[i-1]*inv[i]%Mod;
	#undef N
}
bool M2;
int main(){
	// freopen("yielding.in","r",stdin);
	// freopen("yielding.out","w",stdout);
	srand(time(0)^(*new int));
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	init();
	cin>>n;
	F(i,2,n){
		int x;
		cin>>x;
		e[x].pb(i);
	}
	dfs(1,0);
	ans=f[1][0]*fac[n]%Mod;
	ans=(ans%Mod+Mod)%Mod;
	cout<<ans;
	look_memory;
	look_time;
	return 0;
}
/*
g++ A1.cpp -o A1 -std=c++14 -O2&&./A1

3
1 1

3
1 2

15
1 2 2 2 2 3 3 2 7 7 3 10 3 13
*/