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 <bits/stdc++.h>

#define ll long long 

using namespace std;

ll a,b,c,d;
ll r;
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin>>a>>b>>c>>d;
    r=(b-a+2)-(b/c)-(b/d)+((a-1)/c)+((a-1)/d);
    if (a>=314159265358979323) r+=1;
    cout<<r;
    return 0;
}