#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
const int N = 2000010, MOD = 998244353, INF = 0x3f3f3f3f;
int n, m, w[N];



int e[N], ne[N], h[N], idx, sz[N], son[N];
void add(int a, int b) { e[idx] = b, ne[idx] = h[a], h[a] = idx++; }

ll f[5010][5010];
void dfs(int r) {
    sz[r] = 1;
    if (h[r] == -1) {
        f[r][0] = f[r][1] = 1;
        return;
    }
    for (int i = h[r]; ~i; i = ne[i]) {
        int j = e[i];
        dfs(j);
        sz[r] += sz[j];
        if (sz[son[r]] < sz[j]) son[r] = j;
    }
    ll a = 0;
    for (int i = sz[son[r]] + 1; i; i--) f[r][i] = f[son[r]][i - 1];
    for (int i = h[r]; ~i; i = ne[i]) {
        int j = e[i];
        if (j == son[r]) continue;
        vector<ll> t(sz[r] + 1), a(sz[r] + 2);
        for (int i = 0; i <= sz[r]; i++) t[i] = f[r][i];
        for (int k = 0; k <= sz[j]; k++)
            for (int l = 0; l + k <= sz[r]; l++)
                a[l + k] = (a[l + k] + t[l] * f[j][k]) % MOD;
        for (int j = 0; j <= sz[r]; j++) f[r][j] = a[j];
    }
    for (int j = sz[r] - 1; j >= 0; j--) f[r][j] = (f[r][j] + f[r][j + 1]) % MOD;
}

void solve() {
    memset(h, -1, sizeof h);
    scanf("%d", &n);
    for (int i = 2, a; i < n + 1; i++) {
        scanf("%d", &a);
        add(a, i);
    }
    dfs(1);
    ll res = 0;
    for (int i = 0; i <= n; i++) res = (res + f[1][i]) % MOD;
    printf("%lld\n", res);
}

int main() {
    int T = 1;
    // cin >> T;
    while (T--) solve();
    return 0;
}