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

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

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


def seisu(a, b):
    return (a - (a % b)) / b


def cnt(b, c, d, kobai):
    bc = seisu(b, c)
    bd = seisu(b, d)
    b_kobai = seisu(b, kobai)

    return b - bc - bd + b_kobai


b_num = cnt(b, c, d, kobai)
a_num = cnt(a - 1, c, d, kobai)

ans = b_num - a_num

print(ans)