func_code_string: #include <bits/stdc++.h>   using namespace std;   const int Maxn = 100100;   const int INF = 0x7f7f7f7f;   const double eps = 1e-8;   const double pi = 3.1415926535897932384626433832795;   int main() {     int n;     ios::sync_with_stdio(0);     cin >> n;     cout << n * n / 4 << endl;     for (int i = 1; i <= n / 2; i++)       for (int j = n / 2 + 1; j <= n; j++) cout << i <<     << j << endl;     return 0;   }   