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 PyPy3 (2.4.0) (judge verdict: Accepted)

from fractions import gcd


def li():
    return list(map(int, input().split()))


def multiplier_num(a, b, x):
    if a % x == 0:
        return b // x - a // x + 1
    else:
        return b // x - a // x


if __name__ == "__main__":
    [a, b, c, d] = li()
    lcm = c * d // gcd(c, d)
    # print(lcm)
    # print(multiplier_num(a, b, c))
    # print(multiplier_num(a, b, d))
    # print(multiplier_num(a, b, lcm))
    answer = b - a + 1 - multiplier_num(a, b, c) - multiplier_num(a, b, d) + multiplier_num(a, b, lcm)
    print(answer)

# cでもdでも割り切れない
# 全体からcで割り切れる個数を引き、dで割り切れる個数を引くと
# 　cでもdでも割り切れる個数を引きすぎるので足して戻す
# a以上b以下でxで割り切れる個数
# 　b//x - a//x