func_code_string: #include <bits/stdc++.h>   using namespace std;   list<int> adjList[200002];   int depth[200002];   int sz[200002];   class LCA_binary {     int logn, timer;     vector<int> tin, tout;     vector<vector<int>> up;       public:     void innerdfs(int v, int p) {       tin[v] = ++timer;       up[v][0] = p;       for (int i = 1; i <= logn; ++i) up[v][i] = up[up[v][i - 1]][i - 1];       for (int u : adjList[v]) {         if (u != p) innerdfs(u, v);       }       tout[v] = ++timer;     }     bool is_ancestor(int u, int v) {       return tin[u] <= tin[v] && tout[u] >= tout[v];     }     int lca(int u, int v) {       if (is_ancestor(u, v)) return u;       if (is_ancestor(v, u)) return v;       for (int i = logn; i >= 0; --i) {         if (!is_ancestor(up[u][i], v)) u = up[u][i];       }       return up[u][0];     }     void preprocess(int n, int root) {       tin.resize(n + 3);       tout.resize(n + 3);       timer = 0;       logn = ceil(log2(n));       up.assign(n + 3, vector<int>(logn + 1));       innerdfs(root, root);     }   };   set<int> s;   vector<int> univ;   int deep(int i, int p, int d) {     depth[i] = d++;     if (s.count(i)) univ.push_back(i);     sz[i] = 1;     for (int v : adjList[i])       if (v != p) sz[i] += deep(v, i, d);     return sz[i];   }   int main() {     int n, k;     cin >> n >> k;     for (int i = 0; i < (k << 1); i++) {       int t;       cin >> t;       s.insert(t);     }     for (int i = 1; i < n; i++) {       int a, b;       cin >> a >> b;       adjList[a].push_back(b);       adjList[b].push_back(a);     }     LCA_binary f;     f.preprocess(n, 1);     deep(1, 0, 0);     long long ans = 0LL;     for (int i = 0; i < k; i++)       ans += (long long)(depth[univ[i]] + depth[univ[i + k]] -                          (depth[f.lca(univ[i], univ[i + k])] << 1));     cout << ans <<   n ;     return 0;   }   