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: Runtime Error)

import math
(A,B,C,D)=( int ( x ) for x in input().split(" ") )
E = int ( C * D / math.gcd(C,D) )

print ( B - A - ( math.floor  ( B/C ) - math.ceil ( A/C ) + math.floor  ( B/D ) - math.ceil ( A/D ) + 1 - math.floor  ( B/E ) + math.ceil ( A/E ) - 1 ) )