Problem:
Score : 300 points

Problem Statement

You are given an integer N. Among the integers between 1 and N (inclusive), how many Shichi-Go-San numbers (literally "Seven-Five-Three numbers") are there?

Here, a Shichi-Go-San number is a positive integer that satisfies the following condition:

When the number is written in base ten, each of the digits 7, 5 and 3 appears at least once, and the other digits never appear.

Constraints

1 \leq N < 10^9

N is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the number of the Shichi-Go-San numbers between 1 and N (inclusive).

Sample Input 1

575

Sample Output 1

4

There are four Shichi-Go-San numbers not greater than 575: 357, 375, 537 and 573.

Sample Input 2

3600

Sample Output 2

13

There are 13 Shichi-Go-San numbers not greater than 3600: the above four numbers, 735, 753, 3357, 3375, 3537, 3557, 3573, 3575 and 3577.

Sample Input 3

999999999

Sample Output 3

26484

Solution in Fortran (gfortran v4.8.4) (judge verdict: Accepted)

implicit none
integer(16) N
read*,N
print"(i0)",dfs(.false.,.false.,.false.,0_16)

contains

recursive function dfs(a,b,c,num)result(res)
  implicit none
  logical,intent(in)::a,b,c
  integer(16),intent(in)::num
  integer::res
  res=0
  if(num<=N)then
    if(a.and.b.and.c)res=1
    res = res + dfs(.true., b, c, num*10 + 7)
    res = res + dfs( a,.true., c, num*10 + 5)
    res = res + dfs( a, b,.true., num*10 + 3)
  endif
  return
end function
end