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: Time Limit Exceeded)

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)

func main() {
	sc.Split(bufio.ScanWords)
	sc.Scan()
	a, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}

	sc.Scan()
	b, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}

	sc.Scan()
	c, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}

	sc.Scan()
	d, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}

	cnt := b - a + 1
	var result int
	var share int
	var tmp int

	if a%c == 0 {
		tmp = a / c
	} else {
		tmp = a/c + 1
	}

	for i := c * tmp; i <= b; i = i + c {
		if i%d == 0 {
			share++
		}
		result++
	}

	if a%d == 0 {
		tmp = a / d
	} else {
		tmp = a/d + 1
	}

	for i := d * tmp; i <= b; i = i + d {
		result++
	}

	result = result - share
	result = cnt - result

	fmt.Println(result)
}