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.

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.

Constraints

• $1\leq A\leq B\leq 10^{18}$
• $1\leq C,D\leq 10^9$
• All values in input are integers.

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

见题面 Input 部分

见题面 Output 部分