Divisibility by 4

Let an infinite sequence of numbers, composed as follows:

A_{0 }= 1, A_1 = 12,…,A_9 = 12345678910, A_10 = 1234567891011, ….

That is, each successive term is obtained by assigning the sequence at the end of the previous member for decimal numbers, one greater than the value of the index of the term of the sequence.

It is necessary to determine the total number of members of the sequences that without the rest are divisible by 4, among those whose index belongs to the segment [m, n], where 0 ≤ m ≤ n ≤ 10^18.

Input

The only line of the input file are given two non-negative integers m and n.

Output

The only line of the output file a single integer - the answer of the problem.

Examples