### Problem Statement

The digits 4 and 7 are lucky digits, and all other digits are unlucky. A first level lucky number is a positive integer whose decimal representation is a palindrome that contains only lucky digits. A palindrome is a number that reads the same forward and backward. John and Brus would like to count the number of first level lucky numbers within a specified range.

You are given longs a and b. Return the number of first level lucky numbers between a and b, inclusive.

### Definition

 Class: TheLuckyNumbersLevelOne Method: find Parameters: long, long Returns: long Method signature: long find(long a, long b) (be sure your method is public)

### Constraints

-a will be between 1 and 10^18, inclusive.
-b will be between a and 10^18, inclusive.

### Examples

0)

 `1` `100`
`Returns: 4`
 The first level lucky numbers within this range are 4, 7, 44 and 77.
1)

 `45` `54`
`Returns: 0`
 There are no first level lucky numbers here.
2)

 `477444774` `477444774`
`Returns: 1`
 The given range contains only one integer and it is a first level lucky number.
3)

 `456789123` `789123456`
`Returns: 24`

#### Problem url:

http://www.topcoder.com/stat?c=problem_statement&pm=10832

#### Problem stats url:

http://www.topcoder.com/tc?module=ProblemDetail&rd=14247&pm=10832

Vasyl[alphacom]

#### Testers:

PabloGilberto , ivan_metelsky , StevieT

Brute Force