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)

#ABC_131_C
import fractions

A,B,C,D=list(map(int,input().split()))
underB=B-int(B/C)-int(B/D)+int(B/(C*D//fractions.gcd(C,D)))
underA_1=A-1-int((A-1)/C)-int((A-1)/D)+int((A-1)/(C*D//fractions.gcd(C,D)))

print(underB-underA_1)