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: Wrong Answer)

#include <stdio.h>
long Gcd(long m, long n)
{
	long temp;
	while (m % n != 0)
	{
		temp = n;
		n = m % n;
		m = temp;
	}
	return n;
}

int main(){
    long int A, B, C, D;
    int cnt = 0;
    scanf("%ld %ld %ld %ld", &A, &B, &C, &D);
    int i, j, k;
    long int work=C*D/Gcd(D, C);
    cnt += ((long int)B/C)-((long int)A/C);
    //printf("%ld %ld %ld\n", (long int)B/C, ((long int)A/C), cnt);
    cnt += (A%C==0)?1:0;
    //cnt=0;
    cnt += ((long int)B/D)-((long int)A/D);
    cnt += (A%D==0)?1:0;
    //printf("%ld %ld %ld\n", (long int)B/D, ((long int)A/D), cnt);
    //cnt=0;
    cnt -= ((long int)B/work)-((long int)A/work);
    //printf("%ld %ld %ld\n", ((long int)B/work), ((long int)A/work), cnt);
    printf("%ld", B-A-cnt+1);
}