Divisibility by 8#5892

Divisibility by 8

1 second

64 megabytes

Easy

Consider an infinite numerical sequence defined as follows: $A_{1} = 1$ A_1 = 1, $A_{2} = 12$ A_2 = 12, ..., $A_{10} = 12345678910$ A_{10} = 12345678910, $A_{11} = 1234567891011$ A_{11} = 1234567891011, and so on. The first term is $1$ , and each subsequent term is formed by appending the decimal representation of its index to the end of the previous term's decimal representation.

Your task is to find how many terms in this sequence are divisible by $8$ without a remainder, specifically among those terms whose indices fall within the range $[M, N]$ [M, N].

Input

The input consists of a single line containing two positive integers, $M$ and $N$ ( $0 < M, N \leq 1 0^{18}$ 0 < M, N \leq 10^{18}).

Output

Output a single line containing the answer to the problem.

Examples

Example 1