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