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 C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <iostream>
#include <string>
#include <math.h>
#include <vector>
#include <algorithm>
using namespace std;


string S;
long long N, L, a, b, i, j, Ans = 0, c, d;
long long judge1, judge2, judge3;
int main() {
	cin >> a >> b >> c >> d;
	L = c * d;
	judge2 = int(b / c) - int(a / c);
	if (a%c == 0)
		judge2 += 1;
	judge3 = int(b / d) - int(a / d);
	if (a%d == 0)
		judge3 += 1;
	int tmp;

	if (c < d) {
		tmp = c;
		c = d;
		d = tmp;
	}
	int r;
	r =c % d;
	while (r != 0) {
		c = d;
		d = r;
		r = c % d;
	}
	L = L / d;
	
	judge1 = int(b / L) - int(a / L);
	if (a%L == 0)
		judge1 += 1;

//	cout << judge1 << endl << judge2 << endl << judge3;
	Ans = b - a - (judge2 + judge3 - judge1) + 1;

	cout << Ans;
	return 0;
}