#include <bits/stdc++.h>
using namespace std;
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 << "C";
      } else {
        cout << ".";
      }
    }
    cout << endl;
  }
}
