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