func_code_string: #include <bits/stdc++.h>   using namespace std;   long long n, k, cnt[200005], x, y, ans;   vector<long long> v[200005];   void dfs(long long pos, long long pre) {     long long len = v[pos].size();     for (long long i = 0; i < len; i++) {       long long xx = v[pos][i];       if (xx != pre) {         dfs(xx, pos);         cnt[pos] += cnt[xx];         ans += min(cnt[xx], 2 * k - cnt[xx]);       }     }   }   int main() {     scanf( %lld%lld , &n, &k);     for (long long i = 0; i < 2 * k; i++) {       scanf( %lld , &x);       cnt[x] = 1;     }     for (long long i = 0; i < n - 1; i++) {       scanf( %lld%lld , &x, &y);       v[x].push_back(y);       v[y].push_back(x);     }     dfs(1, 0);     printf( %lld n , ans);   }   