#include <iostream>
#include <string>
using namespace std;

string a;
long long db = 1; // Starts at 1 to account for the number "0"
string current_s; // Use a global string to avoid copying overhead

void dfs()
{
    // Optimization: Check length first.
    // If current string is shorter than 'a', it is numerically smaller.
    if (current_s.size() < a.size())
    {
        db++;
    }
    else
    {
        // If lengths are equal, we must compare lexicographically.
        if (current_s <= a) db++;

        // Optimization: Pruning.
        // We cannot go deeper if we have reached the max length.
        return;
    }

    // Backtracking: Append character -> Recurse -> Remove character
    current_s += '0';
    dfs();
    current_s.pop_back();

    current_s += '3';
    dfs();
    current_s.pop_back();
}

int main()
{
    // Optimization: Speed up C++ I/O
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> a;

    // Reserve memory to prevent re-allocation during recursion
    current_s.reserve(a.size());

    current_s = "3";
    dfs();

    cout << db;
}