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
import sys
from collections import deque
import copy
import math
def get_read_func(fileobject):
    if fileobject == None :
        return raw_input
    else:
        return fileobject.readline


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


def lcm(a, b):
	return a * b // gcd (a, b)

def calc_num(X, C, D, E):
    return X - (X/C + X/D - X/E)

def main():
    if len(sys.argv) > 1:
        f = open(sys.argv[1])
    else:
        f = None
    read_func = get_read_func(f);
    input_raw = read_func().strip().split()
    [A, B, C, D] = [long(input_raw[0]), long(input_raw[1]), long(input_raw[2]), long(input_raw[3])]
    E = lcm(C, D)
    print calc_num(B, C, D, E)  - calc_num(A - 1, C, D, E)

if __name__ == '__main__':
    main()
