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 Go (1.6) (judge verdict: Wrong Answer)

package main

import(
    "fmt"
)

func main() {
    var a, b, c, d int
    fmt.Scan(&a, &b, &c, &d)
    cResult:=calcCount(a, b, c)
    dResult:= calcCount(a, b, d)
    cdResult:=calcCount(a, b, c*d)
    res:=cResult+dResult-cdResult
    fmt.Println(b-a+1-res)
}

func calcCount(head int, tail int, num int) int {
    headMod := head%num
    tailMod := tail%num
    store:=tail-head+1-tailMod-headMod
    if store <= 0 {
        store=-store
    }
    res := store/num+1
    return res
}