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
# coding=utf-8

A, B, C, D = 4, 9, 2, 3
A, B, C, D = 10, 40, 6, 8
A, B, C, D = 314159265358979323, 846264338327950288, 419716939, 937510582
A, B, C, D = map(int, raw_input().split())


def f(d):
    return B / d - (A - 1) / d


def gcd(a, b):
    while b != 0:
        a, b = b, a % b
    return a

E = C / gcd(C, D) * D

good = f(C) + f(D) - f(E)
print B - A + 1 - good
