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: Time Limit Exceeded)

from fractions import gcd
a,b,c,d = map(int,input().split())
if c <=0 or d <= 0:
    print("No")
ans = c * d // gcd(c,d)
i = a
j = a
while True:
    if i % c == 0:
        break
    i += 1
while True:
    if j % d == 0:
        break
    j += 1
k = min(i,j)
while True:
    if k % ans == 0:
        break
    k += 1
ii = (b-i)//c 
jj = (b-j)//d 
kk = (b-k)//ans 
print(b-a-ii-jj+kk)