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
def gcd(x,y):
	if x%y == 0:
		return y
	else:
		return gcd(y,x%y)
A,B,C,D = map(int, raw_input().split())
A = A-1
g = C*D/gcd(C,D)
data = [A/C,A/D,B/C,B/D,A/g,B/g]
print((B-A)-(data[2]+data[3]+data[4]-data[0]-data[1]-data[5]))