#include <iostream>
#include <cmath>
#include <conio.h>
using namespace std;

int main ()
{
    int  n, i = 0;
    double f;

    cout << "n = ";
    cin >> n;

    do
    {
       ++i;
       f = pow(2.0, i);

        } while (f < n);

    cout << i;

    getch ();
    return 0;
    }