#include<cstdio>
#include<algorithm>
using namespace std;
typedef long long LL;

LL a,b,c,d,e;

LL Gcd(LL x,LL y) {
	if(y==0) return x;
	return Gcd(y,x%y);
}
int main() {
	scanf("%lld %lld %lld %lld",&a,&b,&c,&d);
	a--; e=c*d/Gcd(c,d);
	printf("%lld\n",b-a-((b/c-a/c)+(b/d-a/d)-(b/e-a/e)));
	return 0;
}
### 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<cstdio>
#include<algorithm>
using namespace std;
typedef long long LL;

LL a,b,c,d,e;

LL Gcd(LL x,LL y) {
	if(y==0) return x;
	return Gcd(y,x%y);
}
int main() {
	scanf("%lld %lld %lld %lld",&a,&b,&c,&d);
	a--; e=c*d/Gcd(c,d);
	printf("%lld\n",b-a-((b/c-a/c)+(b/d-a/d)-(b/e-a/e)));
	return 0;
}
```