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;

long long Gcd(long long m, long long n){
	long long temp;
	while (m % n != 0)
	{
		temp = n;
		n = m % n;
		m = temp;
	}
	return n;
}

int main(){
  long long A, B, C, D, maxSp, minMt, tmp, result;
  cin >> A >> B >> C >> D;
  result = 0;

  if( C > D){
  	maxSp = Gcd(C, D);
  }else{
    maxSp = Gcd(D, C);
  }
  minMt = C * D / maxSp;

  tmp = (B/C) - ((A-1)/C) + (B/D) - ((A-1)/D) - (B/minMt) - ((A-1)/minMt);
  result = (B-A) + 1 - tmp;
  cout << result << endl;
}