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 Kotlin (1.0.0) (judge verdict: Accepted)

import java.util.*

fun xx(a: Long, b: Long): Long {
    var m = a
    var n = b
    if (m > n) {
        n = a
        m = b
    }
    var k: Long = n % m
    while (k != 0.toLong()) {
        n = m
        m = k
        k = n % m
    }
    return m
}
fun main(args: Array<String>){
	val cin = Scanner(System.`in`)
    val a = cin.nextLong() - 1
    val b = cin.nextLong()
    val c = cin.nextLong()
    val d = cin.nextLong()

    val c_able: Long = b/c - a/c
    val d_able: Long = b/d - a/d
    val cd: Long = c / xx(c.toLong(), d.toLong()) * d
    val cd_able: Long = b/cd - a/cd
    println(b - a - c_able - d_able + cd_able)
}