func_code_string: #include <bits/stdc++.h>   using namespace std;   inline long long add(long long a, long long b, long long p = 1000000007) {     long long c = a + b;     if (c >= p) c -= p;     return c;   }   inline long long sub(long long a, long long b, long long p = 1000000007) {     long long c = a - b;     if (c < 0) c += p;     return c;   }   inline long long mul(long long a, long long b, long long p = 1000000007) {     return ((a % p) * (b % p)) % p;   }   long long power(long long x, long long y, long long p = 1000000007) {     long long res = 1;     x = x % p;     if (x == 0) return 0;     while (y > 0) {       if (y & 1) res = (res * x) % p;       y = y >> 1;       x = (x * x) % p;     }     return res;   }   vector<int> g[200005];   int t = 0;   int tim[500005];   void dfs(int u, int v = -1) {     tim[t++] = u;     for (auto x : g[u]) {       if (x == v) continue;       dfs(x, u);     }     tim[t++] = u;   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     int n;     int a;     cin >> n;     int p[n + 1];     for (int i = 2; i <= n; i++) {       cin >> a;       g[i].push_back(a);       g[a].push_back(i);     }     dfs(1);     map<int, int> mp;     for (int i = 0; i <= 2 * n - 1; i++) {       mp[tim[i]]++;       if (tim[i] == n) break;     }     for (auto it = mp.begin(); it != mp.end(); it++) {       if (it->second == 1) {         cout << it->first <<    ;       }     }     return 0;   }   