PROBLEM STATEMENT

John and Brus believe that the digits 4 and 7 are lucky and all others are not.
According to them, an almost lucky number is a number that contains at most one non-lucky digit in 
its decimal representation.
Return the total number of almost lucky numbers between a and b, inclusive.



DEFINITION
Class:TheAlmostLuckyNumbersDivOne
Method:find
Parameters:long long, long long
Returns:long long
Method signature:long long find(long long a, long long b)


CONSTRAINTS
-a will be between 1 and 10^16, inclusive.
-b will be between a and 10^16, inclusive.


EXAMPLES

0)
4
7

Returns: 4

All numbers between 4 and 7 are almost lucky.

1)
8
19

Returns: 4

Numbers 8, 9, 14 and 17 are almost lucky.

2)
28
33

Returns: 0

No almost lucky numbers here.

3)
12345678900
98765432100

Returns: 91136



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