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().strip().split())

def gcd(x, y):
    if x < y:
        return gcd(y, x)
    if y == 0:
        return x
    return gcd(y, x%y)

def lcm(x, y):
    return (x*y)/gcd(x, y)

L = lcm(C, D)

def interval(l, r, d):
    return (r/d) - (l-1)/d

ans = interval(A, B, 1) - interval(A, B, C) - interval(A, B, D) + interval(A, B, lcm(C, D))
print ans