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>) {
    val (a,b,c,d) = readLine()!!.split(' ').map { s -> s.toLong() }
    //val (n,x) = readLine()!!.split(" ").map { s -> s.toLong() }
    //val L = readLine()!!.split(" ").map { s -> s.toLong() }
    val result = countNumber(b,c,d) - countNumber(a-1L,c,d)
    println(countNumber(b,c,d))
}

fun countNumber(x: Long, c: Long, d: Long): Long {
    var c_cnt = (x / c).toLong()
    var d_cnt = (x / d).toLong()
    var cd_cnt = (x / lcm(c,d)).toLong()
    return(x - c_cnt - d_cnt + cd_cnt)
}

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