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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long a=sc.nextLong();
		long b=sc.nextLong();
		long c=sc.nextLong();
		long d=sc.nextLong();
//A以上  B以下の整数のうち、CでもDでも割り切れないものの個数を出力せよ。

//System.out.println(ans(b,c,d));
//System.out.println(ans(a-1,c,d));
System.out.println(ans(b,c,d)-ans(a-1,c,d));

	}

static public long ans(long a,long c,long d){
	long han=a;

	if(Math.log10(d)+Math.log10(c)-Math.log10(gcd(c,d))>17){
		han=han-(han/c)-(han/d)+((han/c)/d);

		return han;
	}else{
	han=han-(han/c)-(han/d)+(han/(lcm(c,d)));
	return han;
	}
}
static long gcd (long a, long b) {
	long temp;
	while((temp = a%b)!=0) {
		a = b;
		b = temp;
	}
	return b;
}

static long lcm (long a, long b) {
	long temp;
	long c = a;
	c *= b;
	while((temp = a%b)!=0) {
		a = b;
		b = temp;
	}
	return (long)(c/b);
}
}