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

def lcm(a,b):
    return (a/gcd(a,b))*b
    
A = map(int,raw_input('').split())
a = int(A[0])
b = int(A[1])
c = int(A[2])
d = int(A[3])
l = lcm(c,d)
ans = (b-a+1) - ((b/c) - (a-1)/c) - ((b/d) - (a-1)/d) + ((b/l) - (a-1)/l)
print(ans)