#include <iostream>
#include <cmath>

using namespace std;

int main() {
    int n;
    cin >> n;
    int biscuit = 1;
    int count = 0;
    
    while (n > biscuit) {
        biscuit = static_cast<int>(pow(2, count+1));
        count++;
    }
    cout << count << endl;

    return 0;
}