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>

long long int gcd(long long int a,long long int b)
{
	long long int r;
	r=1;
	while(r!=0){
		r=a%b;
		a=b;
		b=r;
	}
	return a;
}

int main(void)
{
	long long int a,b,c,d;
	long long int ans;
	scanf("%lld%lld%lld%lld",&a,&b,&c,&d);
	ans=b-a+1-(b/c-(a-1)/c+b/d-(a-1)/d-b*gcd(c,d)/(c*d)+(a-1)*gcd(c,d)/(c*d));
	printf("%lld",ans);
	return 0;
}