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