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,raw_input().split())

# 1..c
def F(c,x):
    if c<1:return 0
    return c-(c/x)

def gcd(a, b):
	while b:
		a, b = b, a % b
	return a
def lcm(a, b):
	return a * b // gcd (a, b)
L=lcm(C,D)        
print(F(B,C)-F(A-1,C)+F(B,D)-F(A-1,D) - F(B,L)+F(A-1,L))
