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: Wrong Answer)

a,b,c,d = map(int, input().split())
l = c * d
ans = 0
count = 0
if b - a >= l:
  for i in range(a, a+l+1):
    if i % c != 0 and i % d != 0:
      count += 1
  ans = count * ((b - a + 1) // l) + ((b - a + 1) % l)
else:
  for i in range(a, b+1):
    if i % c != 0 and i % d != 0:
      count += 1
  ans += count
print(ans)