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 (GCC 9.2.1) (judge verdict: Wrong Answer)

typedef long long LL;LL a,b,c,d;
LL g(LL x,LL y){if(!y)return x;return g(y,x%y);}
main(){
  scanf("%ld%ld%ld%ld",&a,&b,&c,&d);a--;
  printf("%ld",(b-b/c-b/d+b*g(c,d)/(c*d))-(a-a/c-a/d+a*g(c,d)/(c*d)));
}