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