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)

# coding: utf-8

(a, b, c, d) = [int(i) for i in input().rstrip().split(" ")]


def get_count(target: int):
    start = int(a / target) * target
    if start < a:
        start += target
    end = int(b / target) * target
    if end > b:
        end -= target
    if start > end:
        return 0
    return int((end - start) / target) + 1


def get_kouyaku(num1: int, num2: int):
    if num1 % num2 == 0:
        return num2
    return get_kouyaku(num2, num1 % num2)


def get_koubai(num1: int, num2: int):
    kouyaku = get_kouyaku(num1, num2)
    return kouyaku * int(num1 / kouyaku) * int(num2 / kouyaku)


ans = (b - a + 1) - get_count(c) - get_count(d) + get_count(get_koubai(c, d))

print(ans)