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)

import fractions
def gcd(a,b):
   f=fractions.gcd(a,b)
   f2=a*b//f
   return f2

a,b,c,d=map(int, input().split())
bc=b//c
bd=b//d
bcd=b//gcd(c,d)

a=a-1
ac=a//c
ad=a//d
acd=a//gcd(c,d)

print((b-(bc+bd-bcd))-(a-(ac+ad-acd)))