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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
int main() {
	long long int a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, ans = 0;
	scanf("%lld", &a);
	scanf("%lld", &b);
	scanf("%lld", &c);
	scanf("%lld", &d);
	if (c > d) {
		n = c;
		c = d;
		d = n;
	}

	e = b / c;
	f = a / c;
	g = b / d;
	h = a / d;
	i = e - f;
	j = g - h;
	l = i + j;
	long long int a1 = c;
	long long int b1 = d;


	if (a1 < b1) {
		long long int tmp = a;
		a1 = b1;
		b1 = tmp;
	}
	long long int r = a1 % b1;
	while (r != 0) {
		a1 = b1;
		b1 = r;
		r = a1 % b1;
	}

	k = (c*d) / b1;
	m = b / k;
	n = a / k;
	o = m - n;
	if (a%c == 0 || a % d == 0) {
		p = l - o;
	}else {
	p = l - o - 1;
}
	q = b - a;
	ans = q - p;
	printf("%lld", ans);
	return 0;
}