#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;

#define rep(i,n) for(ll i=0;i<n;++i)
#define all(a) (a).begin(),(a).end()
ll intpow(ll a, ll b){ ll ans = 1; while(b){ if(b & 1) ans *= a; a *= a; b /= 2; } return ans; }
ll modpow(ll a, ll b, ll p){ ll ans = 1; while(b){ if(b & 1) (ans *= a) %= p; (a *= a) %= p; b /= 2; } return ans; }
template<class T> T div_floor(T a, T b) { return a / b - ((a ^ b) < 0 && a % b); }
template<class T> T div_ceil(T a, T b) { return a / b + ((a ^ b) > 0 && a % b); }
template <typename T, typename U> inline bool chmin(T &x, U y) { return (y < x) ? (x = y, true) : false; }
template <typename T, typename U> inline bool chmax(T &x, U y) { return (x < y) ? (x = y, true) : false; }

template<typename T>
ostream &operator<<(ostream &os, const vector<T> &a){
    if (a.empty()) return os;
    os << a.front();
    for (auto e : a | views::drop(1)){
        os << ' ' << e;
    }
    return os;
}

void dump(auto ...vs){
    ((cout << vs << ' '), ...) << endl;
}

#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;

void solve() {
    ll N;
    cin>>N;
    vector<vector<ll>> edge(N);
    vector<ll> par(N,-1);
    rep(i,N-1){
        ll p;
        cin>>p;
        p--;
        edge[p].push_back(i+1);
        par[i+1]=p;
    }
    mint ans=0;
    {
        auto dfs=[&](auto self,ll cp)->vector<mint> {
            vector<mint> r(2,0);
            r[0]=1;
            for (ll np:edge[cp]){
                vector<mint> res=self(self,np);
                vector<mint> nr((ll)r.size()+res.size()-1,0);
                rep(i,(ll)r.size()){
                    rep(j,(ll)res.size()){
                        nr[i+j]+=r[i]*res[j];
                    }
                }
                swap(r,nr);
            }
            rep(i,(ll)r.size()-1){
                r[i+1]+=r[i];
            }
            return r;
        };
        vector<mint> r=dfs(dfs,0);
        rep(i,(ll)r.size()){
            ans+=r[i];
        }
    }
    cout<<ans.val()<<'\n';
    return;
}


int main() {
    cin.tie(0)->sync_with_stdio(0);
    ll T=1;
    while (T--){
        solve();
    }
    return 0;
}