#include <bits/stdc++.h>
#define dbg(i,j) cout<<"I am "<<i<<" = "<<endl<<j<<endl;
#define dbr(name,a) cout<<name<<endl;for(auto x:a)cout<<x<<" ";cout<<endl;
#define DBR(name,a) cout<<name<<endl;for(auto x:a){ for(auto y:x)cout<<y<<" ";cout<<endl;}
#define dbmp(name,a) cout<<name<<endl;for(auto x:a){ cout<<x.first<<"\t"<<x.second<<endl;}
#define dbp(name,a) cout<<name<<endl;cout<<a.first<<"\t"<<a.second<<endl;
#define boost ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;

typedef long long int big;

typedef  long double fig;

big mx(vector<big>& v,big i,big j){
    big m=i;
    for(big z=i+1;z<=j;z++){
        if(v[z]>v[m]){
            m=z;
        }
    }
    return m;
}

big mn(vector<big>& v,big i,big j){
    big m=i;
    for(big z=i+1;z<=j;z++){
        if(v[z]>v[m]){
            m=z;
        }
    }
    return m;
}

int main(){
    big n;
    while(cin>>n){
        //dbg("n",n);
        big t=floorl(log10(n)+2);
        //dbg("t",t);
        fig a=log2(n)+t*log2(10);
        //dbg("a",a);
        fig b=log2(n+1)+t*log2(10);
        //dbg("b",b);
        big result=ceill(a);
        while(result>=b){
            t++;
            a=log2(n)+t*log2(10);
            b=log2(n+1)+t*log2(10);
            result=ceill(a);
        //  dbg("a",a);
        //  dbg("b",b);
        }
        cout<<result<<endl;
    }
    return 0;
}