#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define FORR2(x,y,arr) for(auto& [x,y]:arr)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
template<class T> bool chmax(T &a, const T &b) { if(a<b){a=b;return 1;}return 0;}
template<class T> bool chmin(T &a, const T &b) { if(a>b){a=b;return 1;}return 0;}
//-------------------------------------------------------

int N;
int P[5050];
vector<int> E[5050];
vector<ll> dp[5050];

const ll mo=998244353;
void dfs(int cur) {
	vector<ll> F={0,1};
	int i,j;
	FORR(e,E[cur]) {
		dfs(e);
		vector<ll> T(F.size()+dp[e].size()-1);
		FOR(i,F.size()) FOR(j,dp[e].size()) (T[i+j]+=F[i]*dp[e][j])%=mo;
		swap(F,T);
	}
	dp[cur]=F;
	for(i=dp[cur].size()-2;i>=0;i--) (dp[cur][i]+=dp[cur][i+1])%=mo;
	
}

void solve() {
	int i,j,k,l,r,x,y; string s;
	
	cin>>N;
	for(i=1;i<N;i++) {
		cin>>P[i];
		P[i]--;
		E[P[i]].push_back(i);
	}
	dfs(0);
	ll ret=0;
	FORR(a,dp[0]) ret+=a;
	cout<<ret%mo<<endl;
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}