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 (3.8.2) (judge verdict: Wrong Answer)

import math

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

def lec(a, b):
    # aとbの最小公倍数
    return a * b // math.gcd(a, b)

CD = lec(C, D)
C_num = math.floor(B / C) - math.ceil(A / C) + 1
D_num = math.floor(B / D) - math.ceil(A / D) + 1
CD_num = math.floor(B / CD) - math.ceil(A / CD) + 1

answer = B - A + 1 - C_num - D_num + CD_num

print(answer)