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())

def gcd(m, n):
    while m % n:
        t = n
        n = m % n
        m = t
    return n

def lcm(m, n):
    return m * n / gcd(m, n)

def foo(N, C, D):
    return N - (N / C) - (N / D) + (N / lcm(C, D))

print foo(B, C, D) - foo(A-1, C, D)
