#include <bits/stdc++.h>
#include <atcoder/dsu>
using namespace atcoder;
using namespace std;
using ll = int64_t;
using ull = u_int64_t;
#define ALL(a) (a).begin(), (a).end()
#define endl '\n'
#define Yes cout << "Yes" << endl
#define No cout << "No" << endl

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    ll N;
    cin >> N;
    ll cnt = 0;
    ll tmp = 1;
    while (N > tmp) {
        cnt++;
        tmp *= 2;
    }
    cout << cnt << endl;
}