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())
import math
import fractions
num_C = math.floor(B/C) - math.ceil(A/C) + 1
num_D = math.floor(B/D) - math.ceil(A/D) + 1
def lcm(x, y):
    return (x * y) // fractions.gcd(x, y)
lcm_C_D = lcm(C, D)
num_C_D = math.floor(B/lcm_C_D) - math.ceil(A/lcm_C_D) + 1
ans = (B - A +1) - (num_C + num_D - num_C_D)
print(ans)