#include <bits/stdc++.h>

using namespace std;
int n;

int main() {
    cin >> n;
    double cnt = 0.2;
    int sum = 0;
    for (int i = 1;; i++) {
        if (cnt > n) {
            printf("%d", sum);
            break;
        }
        cnt *= 2;
        sum++;
    }
    return 0;
}