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)

# AtCoder Beginner Contest 131
# C - Anti-Division
import math

def lcm(x, y):
    return (x * y) // math.gcd(x, y)

A,B,C,D=map(int,input().split())
bc=B//C
ac=A//C
cnum=bc-ac

bd=B//D
ad=A//D
dnum=bd-ad


lcmcd=lcm(C,D)
blcmcd=B//lcmcd
alcmcd=A//lcmcd
lcmcdnum=blcmcd-alcmcd


if lcm(C,D)==C*D:
    print(B-A-cnum-dnum+lcmcdnum)
else:
    print(B-A-cnum-dnum+lcmcdnum +1)