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 (GCC 5.4.1) (judge verdict: Time Limit Exceeded)

#include <stdio.h>
    
int main(void)
{
    unsigned long int A, B, C, D, cnt = 0;
    
    scanf("%lu %lu %lu %lu", &A, &B, &C, &D);
    
    for (unsigned long int temp = A; temp <= B; temp++)
    {
        if (temp % C == 0)
        {
            continue;
        }

        if (temp % D == 0)
        {
            continue;
        }

        cnt++;
    }
    
    printf("%lu", cnt);
    
    return 0;
}