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)

A, B, C, D = map(int, input().split())
def GCD(x,y):
  if x%y==0:
    return y
  else:
    return GCD(y, x%y)
GCD(1071, 1029)
def lcm(x, y):
    return (x * y) // gcd(x, y)
  
E = lcm(C, D)
answer = (B-A) - (B//C) - (B//D) + (B//E) + (A//C) + (A//D) - (A//E)
if A%C==0 or A%D==0:
  print(answer)
else:
  print(answer + 1)