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 (Clang 3.8.0) (judge verdict: Time Limit Exceeded)

#include<stdio.h>
int main()
{
    long long int a,b,x,c,d,lcm;
    int e,f,m,i,gcd;
    scanf("%lld%lld%lld%lld",&a,&b,&c,&d);
    e=(int)c;
    f=(int)d;
    if(e>=f)
    {
        m=f;
    }
    else
    {
        m=e;
    }
    for(i=m;i>0;i--)
    {
        if(e%i==0&&f%i==0)
        {
            gcd=i;
            break;
        }
        else
        {
            continue;
        }
    }
    lcm=(c*d)/gcd;
    x=b/c+b/d-b/lcm-(a-1)/c-(a-1)/d+(a-1)/lcm;
    printf("%lld",(b-a+1-x));
}