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>

using namespace std;

int gcd(int x, int y) {
  return y ? gcd(y, x%y) : x;
}

int main(){
    long long int A,B,C,D,e,sum=0,s=0;
    cin >> A >> B >> C >> D;
    sum = B-A+1;
    e = C*D/gcd(C,D);
    s = B/C + B/D - B/e - (A-1)/C - (A-1)/D + (A-1)/e ;
    if(B<C*D){
        s -= D/C;
    }
    cout << sum-s;
    return 0;
}