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())

def gcd(x, y):
    if x > y:
        z = x % y
        if z == 0:
            return y
        else:
        	return gcd(z, y)
    elif x < y:
        z = y % x
        if z == 0:
            return x
        else:
            return gcd(x, z)
    else: # x == y
        return x

lcmCD = int(C * D / gcd(C, D))

# 1 以上 x 以下の整数のうち、C でも D でも割り切れないものの個数
def calc(x):
    return x - (int(x / C) + int(x / D) - int(x / lcmCD))

res = calc(B) - calc(A - 1)
print(res)