import core.bitop;
import std.algorithm;
import std.ascii;
import std.bigint;
import std.conv;
import std.functional;
import std.math;
import std.numeric;
import std.range;
import std.stdio;
import std.string;
import std.random;
import std.typecons;

alias sread = () => readln.chomp();
alias Point2 = Tuple!(long, "y", long, "x");

T lread(T = long)()
{
    return readln.chomp.to!T();
}

T[] aryread(T = long)()
{
    return readln.split.to!(T[])();
}

void scan(TList...)(ref TList Args)
{
    auto line = readln.split();
    foreach (i, T; TList)
    {
        T val = line[i].to!(T);
        Args[i] = val;
    }
}

void minAssign(T, U = T)(ref T dst, U src)
{
    dst = cast(T) min(dst, src);
}

void maxAssign(T, U = T)(ref T dst, U src)
{
    dst = cast(T) max(dst, src);
}

enum MOD = (10 ^^ 9) + 7;

void main()
{
    long N = lread();
    long i = 1;
    long ans;
    while (true)
    {
        char[4] t = ['0', '3', '5', '7'];
        string s;
        long j = i;
        bool[] b = new bool[](4);
        while (j != 0)
        {
            b[j % 4] = true;
            s = t[j % 4] ~ s;
            j /= 4;
        }
        if (!b[0] && b[1 .. $].all!(x => x))
        {
            // writefln("%d %s", i, s);
            if (N < s.to!long)
            {
                writeln(ans);
                return;
            }
            ans++;
        }
        i++;
    }
}
