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: Runtime Error)

import math

def x(k, c, d):
    rl1 = k
    lcm = c*d / math.gcd(c,d)
    ccount = int(rl1 // c)
    dcount = int(rl1 // d)
    if lcm != 0:
        cdcount = int(rl1 // lcm)
    else:
        cdcount = 0

    return int(rl1 - ccount - dcount + cdcount)

a, b, C, D = map(int, input().split())
print(x(b, C, D) - x(a-1, C, D))