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)

def sa(c,d):
    
    if c>d:
        c2=c-d
        if c2<d:
            return c2,d
        else:
            return d,c2
    else :
        c2=d-c
        if c2<c:
            return c2,c
        else:
            return c,c2

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

mp=c*d

c1=c+1-1
d1=d+1-1
for i in range(10000):
    c2,d2=sa(c1,d1)
#    print("c1,d1,c2,d2",c1,d1,c2,d2)    
    if c2<=0:
        break
    c1=c2
    d1=d2

mcm=int(mp/c1)

ac2=int((a-1)/c)
ad2=int((a-1)/d)
am2=int((a-1)/mcm)

bc2=int(b/c)
bd2=int(b/d)
bm2=int(b/mcm)
#print(mcm,ac2,bc2,ad2,bd2,am2,bm2)     

icnt=(bc2-ac2)+(bd2-ad2)-(bm2-am2)
icnt=(b+1-a)-icnt

print(icnt)