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
from fractions import gcd

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

A,B,C,D=map(int, raw_input().split())

C_cnt=B/C-(A-1)/C
D_cnt=B/D-(A-1)/D
CD_cnt=B/lcm(C,D)-(A-1)/lcm(C,D)

print (B-A+1)-C_cnt-D_cnt+CD_cnt
