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<cmath>
using namespace std;
int main()
{
	long long a,b,c,d,s=0,t=0,p=0,q=0,cnt=0;
	cin>>a>>b>>c>>d;
	s=ceil((double)a/c);
	t=b/c;
	p=ceil((double)a/d);
	q=b/d;
	
	for(long long i=s;i<=t;i++)
	{
		if((c*i)%d==0)
			cnt++;
	}
	cout<<s<<" "<<t<<" "<<p<<" "<<q<<" "<<cnt<<" "<<(b-a+1)-(t-s+1)-(q-p+1)+cnt;
}