#!/usr/local/bin/python
# $Id: hash.python,v 1.4 2001/06/10 03:33:57 doug Exp $
# http://www.bagley.org/~doug/shootout/
# with help from from Gustavo Niemeyer

import sys
#sys.setcheckinterval(10000)

def main():
    n = int(sys.argv[1])
    X = {}
    myhex = hex
    for i in xrange(1,n+1):
        X[myhex(i)[2:]] = i
    c = 0
    has_key = X.has_key
    for i in xrange(n, 0, -1):
        c += has_key(`i`)
    print c

main()