n=int(input());mod=998244353
p=[0]+list(map(lambda x:int(x)-1,input().split()))
v=[[] for i in range(n)]
t=[1]*n
for i in range(1,n):
	v[p[i]].append(i)
dp=[[0]*(n+1) for i in range(n)]
for i in range(n-1,-1,-1):
	if len(v[i]):
		dp[i][1]=1;s=1
		for j in v[i]:
			for l in range(t[i],0,-1):
				c=dp[i][l]*dp[j][0]%mod
				for k in range(t[j],0,-1):
					dp[i][l+k]+=dp[j][k]*dp[i][l]%mod
					dp[i][l+k]%=mod
				dp[i][l]=c
			t[i]+=t[j]
		for j in range(t[i],0,-1):
			dp[i][j-1]+=dp[i][j];dp[i][j-1]%=mod
			
	else:
		dp[i][0]=1;dp[i][1]=1
ans=0
for i in range(n+1):
	ans+=dp[0][i]
print(ans%mod)