## Goal

A lucky number is a 10-based number, which has at least a "6" or an "8" in its digits. However, if it has "6" and "8" at the same time, then the number is NOT lucky. For example, "16", "38", "666" are lucky numbers, while "234" , "687" are not.

Now we want to know how many lucky numbers (without leading zeroes) are there between `L` and `R`, inclusive?
Input

**Line 1:** Two integers, `L` and `R`.

Output

**Line 1:** An integer, indicating the amount of lucky numbers between [ `L` , `R` ].