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 (1.14.1) (judge verdict: Accepted)

package main

import (
	"fmt"
)

func gcd(A int, B int) int {

	if B == 0 {
		return A
	}
	return gcd(B, A%B)
}

func lcm(A int, B int) int {

	return A * B / gcd(A, B)
}

func main() {
	// Code for C - Anti-Division
	var A, B, C, D int
	fmt.Scanf("%d %d %d %d", &A, &B, &C, &D)

	A--
	E := B - B/C - B/D + B/lcm(C, D)
	F := A - A/C - A/D + A/lcm(C, D)

	fmt.Println(E - F)
}