func_code_string: #include <bits/stdc++.h>   using namespace std;   map<pair<int, int>, int> id;   vector<int> a[100005];   int main() {     int i, j, k, n;     cin >> n;     cout << n - 1 << endl;     int idd = 1;     for (k = (1); k <= (n - 1); k++) {       cin >> i >> j;       a[i].push_back(j);       a[j].push_back(i);       id[make_pair(i, j)] = idd;       id[make_pair(j, i)] = idd++;       printf( 2 %d %d n , i, j);     }     for (i = (1); i <= (n); i++)       for (j = 1; j < a[i].size(); j++) {         cout << id[make_pair(i, a[i][j - 1])] <<     << id[make_pair(i, a[i][j])]              << endl;       }     return 0;   }   