#include <bits/stdc++.h>
using namespace std;
int main(){
    int N;cin>>N;
    if(N<100){
        cout<<(N-9)/3<<endl;
        return 0;
    }
    int ans=30;
    string S=to_string(N);
    int count=48;
    for(int i=3;i<S.size();i++){
        ans+=count;
        count*=4;
    }
    if(S.at(0)<3){cout<<ans<<endl; return 0;}
    if(S.at(0)<6){cout<<ans+count/3<<endl; return 0;}
    if(S.at(0)<9){cout<<ans+count/3*2<<endl; return 0;}
    cout<<ans+count<<endl;
}