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(void)
{
    long long begin;
    long long end;
    long long divisor_c;
    long long divisor_d;

    cin >> begin >> end >> divisor_c >> divisor_d;


    long long first_nc = 0;
    long long first_nd = 0;
    long long first_ncd = 0;

    first_nc = begin % divisor_c + begin;
    first_nd = begin % divisor_d + begin;
    first_ncd = begin % divisor_c % divisor_d + begin;

    long long divided_count = 0;
    if(first_nc != 0){
        divided_count += (end - first_nc) / divisor_c;

    }
    if(first_nd != 0){
        divided_count += (end - first_nd) / divisor_d;

    }
    if(first_ncd != 0){
        divided_count -= (end - first_ncd) / divisor_c / divisor_d;

    }

    cout << end - begin + 1 - divided_count << endl;
    return 0;
}