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
A,B,C,D=map(int, input().split())
f=C
g=D
while f%g!=0:
  f,g=[g, f%g]
l=C*D//g
m=B//l
n=(A-1)//l
print(B-(B//C)-(B//D)+m-(A-1-((A-1)//C)-((A-1)//D)+n))