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 int lint;

int main(){
    lint a, b, c, d;
    
    
    cin >> a >> b >> c >> d;
    lint ekok = (c*d)/__gcd(c,d);
    lint c_bolum_a = (a-1)/c;
    lint d_bolum_a = (a-1)/d;
    lint cd_bolum_a = (a-1)/ekok;
    lint c_bolum_b = b/c;
    lint d_colum_b = b/d;
    lint cd_bolum_b = b/ekok;
    
    lint res = -c_bolum_a-d_bolum_a+c_bolum_b+d_colum_b+cd_bolum_a- cd_bolum_b;
    cout << b-a+1-res;

    return 0;
}