func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MAXN = 200200;   int n, k, cnt[MAXN];   long long ans;   bool f[MAXN];   vector<int> g[MAXN];   void dfs(int v, int p = -1) {     cnt[v] = f[v];     for (const int &u : g[v])       if (u != p) dfs(u, v), cnt[v] += cnt[u];   }   void solve(int v, int p = -1) {     for (const int &u : g[v])       if (u != p) {         ans += min(2 * k - cnt[u], cnt[u]);         solve(u, v);       }   }   int main() {     scanf( %d %d , &n, &k);     for (int i = 1, x; i <= 2 * k; ++i) scanf( %d , &x), f[x] = true;     for (int i = 1, u, v; i < n; ++i)       scanf( %d %d , &u, &v), g[u].push_back(v), g[v].push_back(u);     dfs(1);     solve(1);     printf( %lld n , ans);   }   