import java.io.File;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Random;
import java.util.Scanner;

class Main{
	
	final long p = 998244353;
	
	long ans=1;
	
	void dfs(int v, int d, ArrayList<Integer>[] g) {
		if (d > 0) ans = ans * d % p;
		for (int u : g[v]) {
			dfs(u, d + 1, g);
		}
	}
	
	void run() throws Exception {
        Scanner sc=new Scanner(System.in);
        PrintWriter pw=new PrintWriter(System.out);
        int N=sc.nextInt();
        ArrayList<Integer>[] g=new ArrayList[N];
        for (int i=0;i<N;++i) g[i]=new ArrayList<>();
        for (int i=1;i<N;++i) {
        	int p=sc.nextInt()-1;
        	g[p].add(i);
        }
        
        dfs(0, 0, g);
        
        System.out.println(ans);
        pw.close();
	}
	
	void generate_random() throws Exception {
		Random rnd=new Random();
		for (int testcase=1;testcase<=5;++testcase) {
			File file=new File("random_"+testcase);
			PrintWriter pw=new PrintWriter(file);
			int N=100000;
			pw.println(N);
			for (int i=2;i<=N;++i) {
				int p=rnd.nextInt(1, i);
				pw.println(p);
			}			
			pw.close();
		}
	}
	
	void generate_line() throws Exception {
		File file=new File("line");
		PrintWriter pw=new PrintWriter(file);
		Random rnd=new Random();
		int N=100000;
		pw.println(N);
		for (int i=2;i<=N;++i) {
			int p=i-1;
			pw.println(p);
		}
		pw.close();
	}
	
	void generate_star() throws Exception {
		File file=new File("star");
		PrintWriter pw=new PrintWriter(file);
		Random rnd=new Random();
		int N=100000;
		pw.println(N);
		for (int i=2;i<=N;++i) {
			int p=1;
			pw.println(p);
		}
		pw.close();
	}
	
    public static void main(String args[]) throws Exception {
    	new Main().run();
    }
    
    void tr(Object...o) {
    	System.out.println(Arrays.deepToString(o));
    }
}