#include<iostream>
#include<sstream>
#include<fstream>
#include<string>
#include<vector>
#include<deque>
#include<queue>
#include<stack>
#include<set>
#include<map>
#include<algorithm>
#include<functional>
#include<utility>
#include<bitset>
#include<cmath>
#include<cstdlib>
#include<ctime>
#include<cstdio>

using namespace std;

#define REP(i,n) for(int i=0;i<int(n);i++)
#define foreach(c,itr) for(__typeof((c).begin()) itr=(c).begin();itr!=(c).end();itr++)
typedef pair<int,int> P;
typedef long long ll;

ll p[70];

int main(void){

	ll N;
	cin >> N;

	if(N==0){
		cout << 0 << endl;
		return 0;
	}

	int i;
	p[1]=1;
	for(i=2;;i++){
		p[i]=2*p[i-1];
		if(p[i]>1e18) break;
	}

	int x;
	for(i=1;i<=65;i++){
		if(p[i]>N){
			x=i-1;
			break;
		}
	}

	cout << x << endl;

	return 0;
}