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 PyPy3 (2.4.0) (judge verdict: Accepted)

def gcd(a,b):
	while b!=0:
		a,b=b,a%b
	return a

def lcm(a,b):
	return a*b//gcd(a,b)

a,b,c,d = map(int,input().split())
a-=1
ac = a//c
ad = a//d
bc = b//c
bd = b//d
cd = lcm(c,d)

if cd <= b:
	print((b-a)-((bc+bd)-(ac+ad))+(b//cd-a//cd))
else:
	print((b-a)-((bc+bd)-(ac+ad)))