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

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

A, B, C, D = [int(i) for i in input().split()]

C_count = math.floor(B/C) - math.ceil(A/C) + 1
D_count = math.floor(B/D) - math.ceil(A/D) + 1
both_count = math.floor(B/lcm(C, D)) - math.ceil(A/lcm(C, D)) + 1
# print(C_count)
# print(D_count)
# print(both_count)
answer = B - A + 1 - (C_count + D_count - both_count)
print(answer)