n = int(input())
P = [-1] + list(map(lambda x: int(x)-1, input().split()))
node = [[] for _ in range(n)]
for i in range(1, n):
    node[P[i]].append(i)

mod = 998244353
E = []
D = [-1] * n
D[0] = 0
A = [0]
while A:
    now = A.pop()
    E.append(now)
    for nxt in node[now]:
        if D[nxt] == -1:
            D[nxt] = D[now] + 1
            A.append(nxt)
dp = [[0, 1] for _ in range(n)]
for now in E[::-1]:
    l = len(dp[now])
    for i in range(l-2, -1, -1):
        dp[now][i] = (dp[now][i] + dp[now][i+1]) % mod
    nxt = P[now]
    if nxt == -1:
        continue
    a = len(dp[now])
    b = len(dp[nxt])
    c = a + b - 1
    ndp = [0] * c
    for ai in range(a):
        for bi in range(b):
            ndp[ai+bi] = (ndp[ai+bi] + dp[now][ai] * dp[nxt][bi]) % mod
    dp[nxt] = ndp

#print(dp[0])
print(sum(dp[0]) % mod)