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().split())

def wareruzu(x):
    if b < x:
        return 0
    start_a = a if a % x == 0 else a - (a % x) + x
    end_b = b - (b % x)
    m = end_b - start_a
    return int(m / x) + 1

all_n = b - a + 1
print(all_n - wareruzu(c) - wareruzu(d) + wareruzu((c*d) / math.gcd(c,d)))