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: Time Limit Exceeded)

#include <bits/stdc++.h>
using namespace std;
#include <iostream>
#include <vector>
#include <cstdlib>
#include <cmath>
#include <math.h>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
using pint = pair<int,int>;
using ll=long long;
using vll = vector<ll>;
using vvll = vector<vector<ll>>;

int main() {
    ll a,b,c,d;cin>>a>>b>>c>>d;    
    ll cnt = 0;
    for(int i=a; i<=b; i++){
        if(i%c!=0 && i%d!=0) cnt+=1;
    }

    cout<<cnt<<endl;
}