Problem:
Score : 300 points

Problem Statement

You are given four integers A, B, C, and D. Find the number of integers between A and B (inclusive) that can be evenly divided by neither C nor D.

Constraints

1\leq A\leq B\leq 10^{18}

1\leq C,D\leq 10^9

All values in input are integers.

Input

Input is given from Standard Input in the following format:

A B C D

Output

Print the number of integers between A and B (inclusive) that can be evenly divided by neither C nor D.

Sample Input 1

4 9 2 3

Sample Output 1

2

5 and 7 satisfy the condition.

Sample Input 2

10 40 6 8

Sample Output 2

23

Sample Input 3

314159265358979323 846264338327950288 419716939 937510582

Sample Output 3

532105071133627368

Solution in Ruby (2.7.1) (judge verdict: Wrong Answer)

data = $stdin.gets
a,b,c,d = data.split(" ").map{|x| x.to_f}
ab = b - a + 1
n_c = ( (b/c).floor -   (a/c).ceil + 1 )
n_d = ( (b/d).floor -   (a/d).ceil + 1 )
lcm_cd = c.to_i.lcm(d.to_i)
n_cd = ( (b/(lcm_cd)).floor - (a/(lcm_cd)).ceil  + 1)
result = (ab - n_c - n_d + n_cd).to_i
puts n_c
puts n_d
puts n_cd
puts result