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>
#include <algorithm>
#include <string>
#include <vector>
using namespace std;

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

int main() {
    long long int a, b;
    long long int c, d;
    cin >> a >> b >> c >> d;
    long long cd;// = (c*d)/gcd(c, d);
    if(c < d) {
        cd = (c*d)/gcd(c, d);
        //cout << (c*d)/gcd(c, d) << endl;
    }
    else {
        cd = (c*d)/gcd(d, c);
    }
    
    long long int div_ac, div_ad, div_bc, div_bd;
    div_ac = (a-1) / c;
    div_ad = (a) / d;
    div_bc = (b-1) / c;
    div_bd = (b) / d;
    long long int div_acd, div_bcd;
    div_acd = (a) / cd;
    div_bcd = b / cd;
    int flag = 0;
    if(a != 0) {
        flag = 1;
    }
    cout << (b-a+1) - ((div_bc+div_bd-div_bcd)
                  - (div_ac+div_ad-div_acd)) << endl;
    return 0;
}