| ||A lucky number is a number whose decimal representation contains only the digits 4 and 7. An almost lucky number is a number that is divisible by a lucky number. For example, 14, 36 and 747 are almost lucky, but 2 and 17 are not. Note that a number can be both lucky and almost lucky at the same time (for example, 747).
You are given longs a and b. Return the number of almost lucky numbers between a and b, inclusive.
|Method signature:||long count(long a, long b)|
|(be sure your method is public)|
|-||a will be between 1 and 10,000,000,000, inclusive.|
|-||b will be between a and 10,000,000,000, inclusive.|
|There are three almost lucky numbers less than or equal to ten - 4, 7 and 8.|
|14 is an almost lucky number.|