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(C, D):
  if C >= D:
    tmp = C
    C = D
    D = tmp
  gcd = 1  
  for i in range(D-C+1):
    dif_1 = D % C
    if C % dif_1 == 0:
      gcd = C
      break
    D = C
    C = dif_1
  return gcd

gcd = gcd(C, D)
lcm = C * D // gcd
a_c = (A-1) // C
a_d = (A-1) // D
b_c = B // C
b_d = B // D
a_lcm = (A-1) // lcm
b_lcm = B // lcm
count = (B - A + 1) - ((b_c - a_c) + (b_d - a_d) - (b_lcm - a_lcm))
print(int(count))