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