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 main(args: Array<String>) {
    val pw = java.io.PrintWriter(System.out)
    Problem.solve(Scanner(System.`in`), pw)
    pw.flush()
}

fun gcd(a: Long, b: Long): Long = if (b == 0L) a else gcd(b, a % b)
fun lcm(a: Long, b: Long): Long = a / gcd(a, b) * b

object Problem {
    fun solve(sc: Scanner, pw: java.io.PrintWriter) {
        val A = sc.next().toLong()
        val B = sc.next().toLong()
        val C = sc.next().toLong()
        val D = sc.next().toLong()
        val E = lcm(C, D)
        val b = (B / C + B / D - B / E)
        val a = ((A - 1) / C + (A - 1) / D - (A - 1) / E)
        val ans = (B - A + 1) - (b - a)
        pw.println(ans)

    }
}