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>
#include <string.h>

int main()
{
    long long int a,b,c,d,e,a1,a2,a3,b1,b2,b3,ans;
    scanf("%lld%lld%lld%lld",&a,&b,&c,&d);
    e=c*d;

    if(a%c==0)  a1=a;
    else a1=((a+c)/c)*c;
    if(a%d==0)  a2=a;
    else a2=((a+d)/d)*d;
    if(a%c==0)  a3=a;
    else a3=((a+e)/e)*e;
    if(a1>b)    a1=0;
    if(a2>b)    a2=0;
    if(a3>b)    a3=0;

    b1=(b/c)*c;
    b2=(b/d)*d;
    b3=(b/e)*e;

    ans=b-a+1-((b1-a1)/c+1+(b2-a2)/d+1)+(b3-a3)/e+1;

    printf("%lld",ans);
    return 0;
}