func_code_string: #include <bits/stdc++.h>   using namespace std;   const int inf = 1e9;   int main() {     int n, d, h;     cin >> n >> d >> h;     if (h * 2 < d || h > n || d > n || h > d || n < d + 1 ||         (h == 1 && d == 1 && (n != 2)))       cout << -1;     else {       if (h == 1) {         for (int i = 2; i <= n; i++) cout << 1 <<     << i << endl;         return 0;       }       for (int i = 1; i <= h; i++) cout << i <<     << i + 1 << endl;       for (int i = 1; i <= d - h; i++)         cout << ((i == 1) ? 1 : i + h) <<     << i + h + 1 << endl;       for (int i = 0; i < n - d - 1; i++) cout << 2 <<     << n - i << endl;     }     return 0;   }   