text: #include <bits/stdc++.h>
  using namespace std;
  
  int main(int argc, char **argv) {
      mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
      int n = 100;
      if (argc > 1) {
          n = atoi( argv[1] );
      }
      set<array<int, 2>> E;
      for(int i=0; i<n; ++i) {
          for(int j=i+1; j<n; ++j) {
              if (i == j) continue;
              int dir = uniform_int_distribution<int>(0, 1)(rng);
              if (dir)
                  E.insert({i, j});
              else
                  E.insert({j, i});
          }
      }
  
      cout << n << " " << E.size() << endl;
      for(auto it : E) cout << it[0] << " " << it[1] << endl;
  }
  
  