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)

# coding: utf-8
a, b, c, d = [int(i) for i in input().split()]
c1, d1 = [d if c < d else c, c if c < d else d]
while d1 > 1:
    e = d1
    d1 = c1 % d1
    c1 = e
e = c * d / e
cnt = (b - a + 1) + int(b / e) - int(a / e) - int(b / c) + int(a / c) - int(b / d) + int(a / d)
print(cnt)