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<iostream>

using namespace std;
typedef long long ll;

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