#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int z = n / 2;
  if (n % 2 == 0) {
    cout << z * n << endl;
  } else {
    long int x = z * z;
    long int y = z + 1;
    y = y * y;
    cout << x + y << 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 << endl;
  }
}
