#include <bits/stdc++.h>
using namespace std;
using ll=long long;
#include <atcoder/modint>
using mint=atcoder::modint998244353;
int main(){
	int n;
	cin>>n;
	vector<vector<int>> graph(n);
	for(int i=1;i<n;i++){
		int p;
		cin>>p;
		graph[p-1].push_back(i);
	}
	auto rec=[&](auto rec,int v)->vector<mint>{
		int m=1;
		vector<mint> dp(m+1);
		dp[1]=1;
		for(int u:graph[v]){
			auto ep=rec(rec,u);
			int k=ep.size()-1;
			vector<mint> ndp(k+m+1);
			for(int i=0;i<=m;i++)for(int j=0;j<=k;j++){
				ndp[i+j]+=dp[i]*ep[j];
			}
			m+=k;
			dp=move(ndp);
		}
		for(int i=m-1;i>=0;i--)dp[i]+=dp[i+1];
		return dp;
					
	};
	auto v=rec(rec,0);
	mint ans=0;
	for(auto x:v)ans+=x;
	cout<<ans.val()<<endl;
}