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)

A,B,C,D = map(int,input().split())

def lcd(a,b):
    return (a*b)/fractions.gcd(a,b)

import fractions

two = B // C
three = B //D

g = int(lcd(C,D))
six = B // (g)

btwo = (A-1) // C
bthree = (A-1) //D
bsix = (A-1) // (g)

a = B - two - three  + six
b = (A-1) - btwo - bthree  + bsix



print(a - b)