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