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

C_ = int(B/C) - int((A-1)/C)
if A % C == 0:                                                                                                                                                                                              
    C_ += 1                                                                                                                                                                                                 
D_ = int(B/D) - int((A-1)/D)
if A % D == 0:                                                                                                                                                                                              
    D_ += 1                                                                                                                                                                                                 

E = C * D / int(fractions.gcd(C, D))
E_ = int(B/E) - int((A-1)/E)
if A % E == 0:                                                                                                                                                                                              
    E_ += 1                                                                                                                                                                                                 

ans = B - A + 1 - C_ - D_ + E_
print(ans)