#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 + 1) / 2) * ((n + 1) / 2) << endl;
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= n; j++) {
      if (i % 2 == 0) {
        cout << (j % 2 == 0 ? "C" : ".");
      } else {
        cout << (j % 2 == 1 ? "C" : ".");
      }
    }
    cout << endl;
  }
  return 0;
}
