#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;
using mint = modint998244353;

mint dp[5010][5010];

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  VI p(n);
  for (int i = 1; i < n; i++) {
    cin >> p[i], p[i]--;
  }
  VI sz(n, 1);
  rep(i, n) dp[i][1] = 1;
  rrep(v, n) {
    rrep(i, sz[v]) dp[v][i] += dp[v][i+1];
    if (v == 0) break;
    int u = p[v];
    rrep(i, sz[u] + 1) {
      mint x = dp[u][i];
      dp[u][i] = 0;
      rrep(j, sz[v] + 1) dp[u][i+j] += x * dp[v][j];
    }
    sz[u] += sz[v];
  }
  mint ans = accumulate(dp[0], dp[0] + sz[0] + 1, mint());
  cout << ans.val() << '\n';
}