#include <bits/stdc++.h>
using namespace std;
 
int main() {
  long a,b,c,d,ans,r,s,t;
  cin>>a>>b>>c>>d;
  ans=(b-a+1);
  s=min(c,d);
  t=max(c,d);
  r=t%s;
  while(r>0){
    t=s;
    s=r;
    r=t%s;
  }
  t=c*d/s;
  ans=ans-(b/c-(a-1)/c+b/d-(a-1)/d-b/t+(a-1)/t);
  cout<<ans;
}
### Prompt

Create a solution in CPP for the following problem:

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.

Examples

Input

4 9 2 3


Output

2


Input

10 40 6 8


Output

23


Input

314159265358979323 846264338327950288 419716939 937510582


Output

532105071133627368

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
 
int main() {
  long a,b,c,d,ans,r,s,t;
  cin>>a>>b>>c>>d;
  ans=(b-a+1);
  s=min(c,d);
  t=max(c,d);
  r=t%s;
  while(r>0){
    t=s;
    s=r;
    r=t%s;
  }
  t=c*d/s;
  ans=ans-(b/c-(a-1)/c+b/d-(a-1)/d-b/t+(a-1)/t);
  cout<<ans;
}
```