/* vim: set ts=4 sts=4 sw=4 si foldmethod=marker: */
// {{{ includes

// IO
#include <string>
#include <iostream>
#include <iomanip>
#include <sstream>
#include <iterator>

// Utility
#include <cassert>
#include <algorithm>
#include <numeric>
#include <functional>
#include <cstdlib>
#include <cmath>
#include <gmp.h>
#include <stdexcept>

// Data structures
#include <vector>
#include <list>
#include <set>
#include <stack>
#include <queue>
#include <ext/hash_map>
#include <tr1/unordered_set>
#include <map>

// I want easy access to STL and things like hash_map
using namespace std;
using namespace std::tr1;
using namespace __gnu_cxx;

// Needed for hash_map<string/X>
namespace __gnu_cxx                                                                                 
{                                                                                             
    template<> struct hash<std::string>                                                       
    {                                                                                           
        size_t operator()(const std::string& x) const                                           
        {                                                                                         
            return hash<const char*>()(x.c_str());                                              
        }                                                                                         
    };                                                                                          
}     
// }}}
// {{{ utility routines and such

// stolen from http://www.ddj.com/cpp/184403801
template<class T>
class StringTok
{
public:
    StringTok(const T& seq, typename T::size_type pos = 0) : seq_(seq) , pos_(pos) { }
    T operator()(const T& delim);

private:
    const T& seq_;
    typename T::size_type pos_;
};

template<class T>
T StringTok<T>::operator()(const T& delim)
{
    T token;
    if(pos_ != T::npos)
    {
        // start of found token
        typename T::size_type first(seq_.find_first_not_of(delim.c_str(), pos_));
        if (first != T::npos)
        {
            // length of found token
            typename T::size_type num(seq_.find_first_of(delim.c_str(), first) - first);

            // do all the work off to the side
            token = seq_.substr(first, num);    
            
            // done; now commit using
            // nonthrowing operations only
            pos_ = first + num;                            
            if (pos_ != T::npos) ++pos_;                
            if (pos_ >= seq_.size()) pos_ = T::npos; 
        }
    }
    return token;
}

// stolen from http://www.gotw.ca/gotw/029.htm for case-insensitive lexicographic compares  
struct ci_char_traits : public std::char_traits<char>
{
    static bool eq(char c1, char c2) { return toupper(c1) == toupper(c2); }
    static bool ne(char c1, char c2) { return toupper(c1) != toupper(c2); }
    static bool lt(char c1, char c2) { return toupper(c1) <  toupper(c2); }
    static int compare(const char* s1, const char* s2, size_t n) { return strncasecmp(s1, s2, n); }
    static const char* find(const char* s, int n, char a) { while(n-- > 0 && toupper(*s) != toupper(a)) { ++s; } return s; }
};

// no boost makes c++ angry; lexical cast comes in handy for string <=> int conversion without expliucitly writing out the streams all the time.
template <typename T, typename S>
T lexical_cast(const S& arg)
{
    stringstream interpreter;
    T result;
    if (!(interpreter << arg) || !(interpreter >> result) || !(interpreter >> std::ws).eof()) throw logic_error("bad lexical_cast");
    return result;
}


// }}}
// {{{ utility typedefs
typedef vector<string> vs;
typedef vector<int> vi;
typedef std::basic_string<char, ci_char_traits> ci_string; 
// }}}
// {{{ problem-specific typedefs
// }}}

int main()
{
    const long double log2l10(log2l(10));
    long double n;
    while (cin >> n)
    {
        const long double log2ln(log2l(n));
        const long double log2lnp1(log2l(n+1));
        for (long double x(floorl(log10l(n)) + 2);; ++x)
        {
            const uint32_t a(static_cast<uint32_t>(ceill(log2ln + x * log2l10)));
            if (a != static_cast<uint32_t>(ceill(log2lnp1 + x * log2l10)))
            {
                cout << a << endl;
                break;
            }
        }
    }
    return 0;
}