func_code_string: #include <bits/stdc++.h>   using namespace std;   long long t, n, i, b[1010], ta, tb, k1, a[1010], tem, x[1010], y[1010], k2, tom;   vector<long long> v[1010];   void dfs(long long aa, long long bb) {     b[aa] = bb;     long long ii;     for (ii = 0; ii < v[aa].size(); ii++)       if (!b[v[aa][ii]]) dfs(v[aa][ii], bb);   }   int main() {     cin >> t;     while (t--) {       cin >> n;       for (i = 1; i <= n; i++) v[i].clear();       for (i = 1; i <= n; i++) b[i] = 0;       for (i = 1; i < n; i++) {         cin >> ta >> tb;         v[ta].push_back(tb);         v[tb].push_back(ta);       }       for (i = 1; i <= n; i++) b[i] = 0;       for (i = 1; i <= n; i++) x[i] = 0;       for (i = 1; i <= n; i++) y[i] = 0;       cin >> k1;       for (i = 1; i <= k1; i++) {         cin >> a[i];         b[a[i]] = a[i];         x[a[i]] = 1;       }       for (i = 1; i <= k1; i++) dfs(a[i], a[i]);       cin >> k2;       for (i = 1; i <= k2; i++) {         cin >> ta;         y[ta] = 1;       }       cout <<  B   << ta << endl;       cin >> tem;       if (x[tem])         cout <<  C   << tem << endl;       else {         cout <<  A   << b[tem] << endl;         cin >> tom;         if (y[tom])           cout <<  C   << b[tem] << endl;         else           cout <<  C   << -1 << endl;       }     }   }   