#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  if (n % 2 == 0)
    cout << (n * n) / 2 << endl;
  else
    cout << (n / 2) * (n / 2) + (n / 2 + 1) * (n / 2 + 1) << endl;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= n; j++)
      if ((i + j) % 2 == 0)
        cout << "C";
      else
        cout << ".";
    cout << endl;
  }
}
