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,fractions
a=list(map(int,input().split()))
A=a[1]-a[0]+1
B=math.floor(a[1]/a[2])-math.floor(a[0]/a[2])
if a[0]==B*a[2]:
  B+=1
C=math.floor(a[1]/a[3])-math.floor(a[0]/a[3])
d=a[2]*a[3]/fractions.gcd(a[2],a[3])
D=math.floor(a[1]/d)-math.floor(a[0]/d)
print(A-B-C+D)