func_code_string: #include <bits/stdc++.h>   using namespace std;   const int64_t inf = 1e18;   vector<vector<int64_t> > adj;   int64_t inp() {     int64_t x;     cin >> x;     return x;   }   vector<int64_t> level;   int64_t res = 0;   void dfs(int64_t u, int64_t LV = 0) {     level[u] = LV;     res = max(res, LV);     for (auto v : adj[u]) {       dfs(v, LV + 1);     }   }   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     for (int64_t _ = (1); _ >= (1); _--) {       int64_t n;       cin >> n;       adj.resize(n + 1);       level.resize(n + 1);       for (int64_t node = (1); node <= (n); node++)         adj[max(inp(), int64_t(0))].push_back(node);       dfs(0);       cout << res;     }     return 0;   }   