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 kosuu(a, b, hoge):
    mae = a // hoge
    if a%hoge == 0:
        mae -= 1
    ato = b // hoge
    wareru = ato - mae
    return wareru

def gcd(x, y):
    while y > 0:
        x, y = y, x%y
    return x

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

c_kosuu = kosuu(A,B,C)
d_kosuu = kosuu(A,B,D)
cd_kosuu = kosuu(A,B,lcm(C,D))

# cd_kosuu

print(B-A+1-(c_kosuu+d_kosuu-cd_kosuu))