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)

#入力取得
A, B, C, D = map(int, input().split())


def gcd(a, b):
	while b:
		a, b = b, a % b
	return a


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



lcm = lcm(C ,D)


num_all = B - A + 1


ans = 0

z_a_c = int((A-1) / C)
z_b_c = int(B / C)

z_a_b_c = z_b_c - z_a_c


z_a_d = int((A-1) / D)
z_b_d = int(B / D)

z_a_b_d = z_b_d - z_a_d

z_a_l = int((A-1) / lcm)
z_b_l = int(B / lcm)

z_a_b_l = z_b_l - z_a_l


ans = num_all - z_a_b_c - z_a_b_d + z_a_b_l


print(ans)