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>

using namespace std;

int main()
{
    long long a,b,c,d;
    long long sum=0;
    long long min1,min2;
    cin>>a>>b>>c>>d;
    for(int i=a;;i++)
    {
        if(i%c==0)
            {
                min1=i;
                break;
            }
    }
    //cout<<min1<<endl;
    for(int i=a;;i++)
    {
        if(i%d==0)
            {
                min2=i;
                break;
            }
    }
    //cout<<min2<<endl;
    long long q;
    long long w;
    long long e;
    for(int i=1;;i++)
    {
        if(min1+i*c>b)
        {
            q=i-1;
            //cout<<q<<endl;
            break;
        }
    }
    for(int i=1;;i++)
    {
        if(min2+i*d>b)
        {
            w=i-1;
            //cout<<w<<endl;
            break;
        }
    }
    for(int i=1;;i++)
    {
        if(a+i*c*d>b)
        {
            e=i-1;
            break;
        }
    }
    cout<<b-a-q-w-e<<endl;
    return 0;
}