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)

import fractions

def antidiv(x,l,c,d):
    if x == l or x < 0:
        return l - (l // c) - (l // d) + 1
    else:
        return x - (x // c) - (x // d) 

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

l = (c*d)//fractions.gcd(c,d)


aq = a // l
ar = a % l
bq = b // l
br = b % l
#print(br)

qq = bq - aq - 1
r1 = antidiv(l,l,c,d) - antidiv(ar-1,l,c,d)
r2 = antidiv(br,l,c,d)

if a!=b:
    ans = qq * antidiv(l,l,c,d) + r1 + r2
elif a % c != 0 and a % d != 0:
    ans = 1
else:
    ans = 0


print(ans)