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: Wrong Answer)

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

def getAns(a, b, c):
  num_c = b // c - a // c
  return num_c

a, b, c, d = map(int, input().split())

# cについて
num_c =getAns(a,b,c)
#print(num_c)

# dについて
num_d =getAns(a,b,d)
#print(num_d)

# cとdの公倍数について
cd = c * d // gcd(c,d)
num_cd = getAns(a,b,cd)
#print(num_cd)

print(b - a + 1 - (num_c + num_d - num_cd))