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
import fractions

def main():

    A,B,C,D = (int(i) for i in input().split())

    CD = C * D / fractions.gcd(C,D)
    #print("CD = ", CD)

    count_C = (B//C - (A-1)//C)
    #print("count_C = ", count_C)

    count_D = (B//D - (A-1)//D)
    #print("count_D = ", count_D)

    count_CD = (B//CD - (A-1)//CD)
    #print("count_CD = ", count_CD)

    print(int(B-A+1 - (count_C + count_D - count_CD)))

if __name__ == '__main__':
    main()