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: Accepted)

from fractions import gcd
a,b,c,d = map(int,input().split())
e = int(c*d/gcd(c,d))
n1 = b//c-a//c if a%c != 0 else b//c-a//c+1
n2 = b//d-a//d if a%d != 0 else b//d-a//d+1
n3 = b//e-a//e if a%e != 0 else b//e-a//e+1
print(b-a+1-n1-n2+n3)