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