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: Accepted)

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;

ll gcd(ll a,ll b)
{

    if(b==0)
        return a;
    else
        return gcd(b,a%b);
}

ll lcm(ll a,ll b)
{
    return (a/(gcd(a,b)))*b;

}

int main()
{
    ll t=1;


    while(t--)
    {
        ll a,b,c,d;
        //cout<<lcm(3,4)<<endl;
        cin>>a>>b>>c>>d;
        ll tot=b-a+1;
        ll a1=(a-1)/c+(a-1)/d-((a-1)/lcm(c,d));
        ll b1=b/c+b/d-(b/lcm(c,d));
        //ans= tot-ans;
        //cout<<a1<<" "<<b1<<" "<<tot<<endl;
        cout<<tot-(b1-a1)<<endl;

    }




}