func_code_string: #include <bits/stdc++.h>   using namespace std;   int n;   int k;   int main() {     cin >> n >> k;     int l = (n - 1) / k * 2 + ((n - 1) % k != 0) + ((n - 1) % k >= 2);     cout << l << endl;     for (int i = 1; i < n; i++) {       if (i <= k)         cout << i + 1 <<     << 1 << endl;       else         cout << i + 1 <<     << i + 1 - k << endl;     }     return 0;   }   