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 Python (3.4.3) (judge verdict: Wrong Answer)

import math
a,b,c,d=map(int, input().split())
def gcd(a, b):
	while b:
		a, b = b, a % b
	return a
	
e = (c * d // gcd(c, d))
 
 
f=math.floor((a-1)/c) 
g=math.floor(b/c) 
h=math.floor((a-1)/d) 
k=math.floor(b/d) 
l=math.floor((a-1)/e)
m=math.floor(b/e)
x=round(b-a+1)
y=round(g-f)
z=round(k-h)
w=round(m-l)
print(x-y-z+w)