8503: The Almost Lucky Numbers

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.

Each line contains two integers a,b<=1,000,000

For each line of input,output the total number of almost lucky numbers between a and b, inclusive.

4 7
8 19

4
4