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: Runtime Error)

a,b,c,d = map(int,input().split())
from fractions import gcd
cd_gcd = gcd(c,d)
lcm= c*d // ab_gcd
divs = lcm//c + lcm//d - 1

ans = 0
ans += int((b-a)/lcm)*divs
for i in range(a % lcm, b%lcm+lcm+1):
  if not i % c or not i % d:
    ans += 1
print(b-a - ans)