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)

a,b,c,d = map(int,input().split())

def divide (x):
    p = x // c
    q = x // d
    r = x // lcm_ab
    return p,q,r

def gcd(x,y):
    while y:
        x,y = y,x%y
    return x

def lcm(x,y):
    return x*y//gcd(x,y)

lcm_ab = lcm(a,b)
ac,ad,la = divide(a)
bc,bd,lb = divide(b)

ans = (b-a)-(bc-ac)-(bd-ad)+(lb-la)+1
print(ans)