func_code_string: #pragma GCC optimize( Ofast ,  unroll-loops ,  no-stack-protector )       #include <bits/stdc++.h>       using namespace std;      #define all(a) (a).begin(), (a).end()   #define sz(a) (int)(a).size()      using ll = long long;   using ld = long double;    // using ld = __float128;   using pii = pair<int, int>;   using pll = pair<ll, ll>;   using uint = unsigned int;   using ull = unsigned long long;      mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());   default_random_engine generator;      void solve();      int main() {   #ifdef LOCAL       freopen( input.txt ,  r , stdin);       // freopen( output.txt ,  w , stdout);    #endif           ios_base::sync_with_stdio(false);       cin.tie(0);       cout.tie(0);       cout << setprecision(10) << fixed;       cerr << setprecision(10) << fixed;          int tests = 1;       // cin >> tests;          for (int test = 1; test <= tests; ++test) {           // cout <<  Case #  << test <<  :  ;           solve();       }      #ifdef LOCAL       cerr <<  Time:   << double(clock()) / CLOCKS_PER_SEC << endl;   #endif   }      // -----------------------------------------------------------------       const int MAXN = 200200;   vector<int> g[MAXN];   int w[MAXN];      vector<int> arr;   int dfs(int v, int p = -1) {       arr.push_back(v);       w[v] = 1;       for (int u : g[v]) {           if (u == p) {               continue;           }           w[v] += dfs(u, v);       }       return w[v];   }      vector<int> f;      bool check(int root, int k) {       arr.clear();       dfs(root);       if (sz(arr) != f[k]) {           return false;       }       if (k <= 1) {           return true;       }          for (int v : arr) {           if (w[v] == f[k - 1] || w[v] == f[k - 2]) {               int u;               for (int uu : g[v]) {                   if (w[uu] > w[v]) {                       u = uu;                   }               }                  for (int i = 0; i < sz(g[u]); ++i) {                   if (g[u][i] == v) {                       swap(g[u][i], g[u].back());                       g[u].pop_back();                       break;                   }               }               for (int i = 0; i < sz(g[v]); ++i) {                   if (g[v][i] == u) {                       swap(g[v][i], g[v].back());                       g[v].pop_back();                       break;                   }               }                  if (w[v] == f[k - 1]) {                   if (!check(v, k - 1)) {                       return false;                   }                   if (!check(u, k - 2)) {                       return false;                   }               } else {                   if (!check(v, k - 2)) {                       return false;                   }                   if (!check(u, k - 1)) {                       return false;                   }               }               return true;           }       }       return false;   }      void solve() {         int n;       cin >> n;          int k = 2;       f = {1, 1};       for (; f.back() < n; ++k) {           f.push_back(f[k - 2] + f[k - 1]);       }          for (int i = 1; i < n; ++i) {           int u, v;           cin >> u >> v;           --u; --v;           g[u].push_back(v);           g[v].push_back(u);       }          cout << (check(0, sz(f) - 1) ?  YES n  :  NO n );   }      