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 <vector>
#include <string>
#include <algorithm>

using namespace std;

int main(){
    long a,b,c,d;
    cin >> a >> b>> c >> d;
    long ans = 0;
    long  x = (b/c - (a-1)/c);
    long  y =  (b/d - (a-1)/d);
    long  z =  (b/(c*d) - (a-1)/(c*d));
    ans = (b-a+1) - (x+y-z);
    if(c==d){
        ans=(b-a+1) - b/c +(a-1)/c;
        cout << ans << endl;
    }else
    {
        cout << ans << endl;
    }
}