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;
#define ll unsigned long long int
ll gcd(ll a,ll b)
{
    if (b == 0) 
        return a; 
    return gcd(b, a % b);
}
int main()
{
    ll a,b,c,d,count,common;
    cin>>a>>b>>c>>d;
    common=gcd(c,d);
    common=(c*d)/common;
    double a1,b1,c1,d1;
    a1=a;b1=b;c1=c;d1=d;
    double p1,p2;
    
    p1=a1/c1;p2=b1/c1;
    ll dif=p2-p1;
    count=dif+1;
    if((p1<1)&&(p2<1)){count=count-1;}
    
    p1=a1/d1;p2=b1/d1;
    dif=p2-p1;
    count=count+dif+1;
    if((p1<1)&&(p2<1)){count=count-1;}
    
    p1=a1/common;p2=b1/common;
    dif=p2-p1+1;
    count=count-dif;
    if((p1<1)&&(p2<1)){count=count+1;}
    
    count=b-a+1-count;
    
    cout<<count;
}