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 sub(int C, int D);

int main(void) {
	int A, B, C, D, CD;
	scanf("%d%d%d%d", &A, &B, &C, &D);
	CD = sub(C, D);
	printf("%d\n", B - (B / C + B / D - B / (C * D / CD)) - (A - 1 - ((A - 1) / C + (A - 1) / D - (A - 1) / (C * D / CD))));
	return 0;
}

int sub(int C, int D) {
	int a;
	if (C < D) {
		int tmp;
		tmp = C;
		C = D;
		D = tmp;
	}
	do{
		a = C % D;
		C = D;
		D = a;
	} while (D != 0);
	return C;
}