#include <bits/stdc++.h>
using namespace std;
#pragma GCC target("avx")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
typedef long long ll;
typedef pair<ll,ll> prl;
typedef vector<ll> vcl;
typedef map<ll,ll> mapl;
typedef unordered_map<ll,ll> umap;
#define pb push_back
#define all(v) v.begin(), v.end()
#define rep(i,a,b) for(ll i=a;i<=b;i++)
#define repi(i,a,b) for(int i=a;i<=b;i++)
#define repr(i,a,b) for(ll i=a;i>=b;i--)
#define reps(i,v) for(ll i=0;i<v.size();i++)
template<typename T> void chmin(T &a, const T &b) { a = min(a, b); }
template<typename T> void chmax(T &a, const T &b) { a = max(a, b); }
const ll mod = 998244353;

ll mypow(ll px, ll py){
	if(py == 0) return 1;
	if(py % 2 == 0) return mypow((px * px), py / 2);
	else return (px * mypow(px, py - 1));
}

int main() {
    // your code goes here
    ll n,ans=0,kt,k[40],mm=0;
    bool it=false;
    cin >> n;
    rep(i,10,min(99ll,n)){
    	if(i%3==0) ans++;
    }
    n=n/3;
    if(n<100) kt=2;
    else if(n<1000) kt=3;
    else if(n<10000) kt=4;
    else if(n<100000) kt=5;
    else if(n<1000000) kt=6;
    else if(n<10000000) kt=7;
    else if(n<100000000) kt=8;
    else if(n<1000000000) kt=9;
    else kt=10;
    if(kt==2){
    	cout << ans << endl;
    	return 0;
    }
    rep(i,3,kt-1){
    	ans+=3*mypow(4,i-1);
    }
    rep(i,1,kt){
    	k[i]=n%10;
    	n=n/10;
    }
    repr(i,kt,1){
    	if(i==kt){
    		mm=min(3ll,k[i]);
    		if(k[i]<=3) it=true;
    	} else {
    		mm*=4;
    		if(it){
    			if(k[i]<=3){
    				mm-=(3-k[i]);
    			} else {
    				it=false;
    			}
    		}
    	}
    	
    }
    cout << ans+mm << endl;
    return 0;
}