func_code_string: #include <bits/stdc++.h>   using namespace std;   constexpr long long mod = 1000000007;   pair<long long, long long> dfs(int v, const vector<vector<int>> &children,                                  const vector<int> &black) {     long long zero = 0;     long long one = 0;     (black[v] ? one : zero) = 1;     for (const auto &child : children[v]) {       const auto result = dfs(child, children, black);       long long t_zero = (zero * result.second + zero * result.first) % mod;       one =           (one * result.second + zero * result.second + one * result.first) % mod;       zero = t_zero;     }     return {zero, one};   }   int main() {     cin.tie(nullptr);     ios::sync_with_stdio(false);     int n;     cin >> n;     vector<vector<int>> children(n);     for (int i = 1; i < n; ++i) {       int p;       cin >> p;       children[p].emplace_back(i);     }     vector<int> black(n);     for (auto &e : black) cin >> e;     const auto ans = dfs(0, children, black);     cout << ans.second << endl;     return EXIT_SUCCESS;   }   