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)

import math

A,B,C,D = map(int, input().strip().split())

def lcm_base(x, y):
    return (x * y) // math.gcd(x, y)

ans = 0
lcm = lcm_base(C,D)
c_num = B//C - (A-1)//C 
d_num = B//D - (A-1)//D
diff = B//lcm - (A-1)//lcm

print(B-A+1-(c_num+d_num-diff))