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 Python (3.4.3) (judge verdict: Runtime Error)

from math import floor
 
def gcm(x,y):
  r=x%y
  while r==0:
    x=y
    y=r
    r=x%y
  return y
 
def lcm(x,y):
  return x*y/gcm(x,y)
 
def numantidiv(a,b,c):
    r=a-floor(a/b)+floor(a/c)-floor(a/lcm(b,c))
    return r
 
a,b,c,d=(int(x) for x in input().split())
ans=numantidiv(b,c,d)-numantidiv(a-1,c,d)
print(ans)