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>
#include <numeric>

using namespace std;

long gcd(long m, long n){

	while (m % n != 0)
	{
		long temp = n;
		n = m % n;
		m = temp;
	}
	return n;
}


int main(){
 long a,b,c,d;
  cin >> a >> b >> c >> d;
  long resb,resa;
  long cd;
  cd=c*d/gcd(c,d);
  
  resa=(a-1)-a/c-a/d+a/cd;
  resb=b-b/c-b/d+b/cd;  
  
 
  cout << resb-resa << endl;
}