IMPA/p11636/p11636.cpp

#include <iostream>
#include <cmath>

using namespace std;

int main(int argc, char *argv[])
{
    int number_of_lines = 0, index = 1;


    while(cin >> number_of_lines)
    {
        if(number_of_lines < 0)
            break;

        cout << "Case " << index++ << ": " << ceil(log2(number_of_lines)) << endl;
    }

    return 0;
}