#include <bits/stdc++.h>
using namespace std;
const int maxN = 1e5;
long long int n;
int main() {
  cin >> n;
  cout << (n * n + 1) / 2 << endl;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      if ((i + j) % 2)
        cout << ".";
      else
        cout << "C";
    }
    cout << endl;
  }
  return 0;
}
