Problem:
Score : 300 points

Problem Statement

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.

Sample Input 1

4 9 2 3

Sample Output 1

2

5 and 7 satisfy the condition.

Sample Input 2

10 40 6 8

Sample Output 2

23

Sample Input 3

314159265358979323 846264338327950288 419716939 937510582

Sample Output 3

532105071133627368

Solution in PyPy3 (2.4.0) (judge verdict: Accepted)

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

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

def cntNum(n, x, y):
    return n - (n//x+n//y-n*gcd(x, y)//(x*y))


if A%C != 0 and A%D:
    print(cntNum(B, C, D) - cntNum(A, C, D) + 1)
else:
    print(cntNum(B, C, D) - cntNum(A, C, D))