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)

def gcd(i,j):
  if i > j:
    tmp = i
    i = j
    j = tmp
  while i != 0:
    tmp = i
    i = j%i
    j = tmp
  return j
def lcm(i,j):
  return i*j//gcd(i,j)  
def main():
  a,b,c,d = map(int,input().split())
  ans = b-a+1
  ans -= (b//c - (a-1)//c) + (b//d - (a-1)//d) - (b//lcm(c,d) -(a-1)//lcm(c,d))
  print(ans)


main()