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 b > a:
    a,b = b,a
  while b:
    a, b = b , (a%b)
  return a

  
a,b,c,d = map(int,input().split())
g = c*d // gcd(c,d)
num = g - (g//c) - (g//d) + 1
n_a = (a//g) + (a%g != 0)
n_b = (b//g) + (b%g != 0)


count = 0

if n_b == n_a:
  mi = (a-1)-((n_a-1)*g)
  mib = b - (n_b -1)*num
  count += (mib - (mib//c) - (mib//d)) - (mi - (mi//c) - (mi//d))
elif n_b - n_a == 1 :
  mi = (a-1)-((n_a-1)*g)
  count += num - (mi - (mi//c) - (mi//d))
  nb = b-(n_b-1)*g
  count += nb - (nb//c) - (nb//d)
else:
  count = 0
  #count += num * (n_b - n_a - 1)
  mib = b - (n_b-1)*num
  mi = a-1
  count += (b - (b//c) - (b//d)) - (mi - (mi//c) - (mi//d)) + (n_b - n_a)
  
  
print(count)