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: Wrong Answer)

fun main(args: Array<String>) {
    var (a, b, c, d) = readLine()!!.split(" ").map { it.toLong() }
    val ran = b - a + 1
    if (c == 1L || d == 1L) {
        println(0)
        return
    }
    val cc = b / c - a / c
    val dd = b / d - a / d
    val cd = c * d / gcd(c, d)
    val ccdd = b / cd - a / cd
    println(ran - cc - dd + ccdd)
}

fun gcd(x: Long, y: Long): Long {
    if (x < y) return gcd(y, x)
    if (y == 0L) return x
    return gcd(y, x % y)
}