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)

# coding: utf-8
import re
import bisect
from datetime import datetime as dt
import bisect
import fractions

def gcd(a, b):
    return fractions.gcd(a, b)

def lcm(a, b):
    return a * b / gcd(a, b)

def calc(n, a, b):
    return int(n/a) + int(n/b) - int(n/lcm(a,b))

if __name__ == '__main__':
    a, b, c, d = map(int, input().split())
    ans = calc(b, c, d) - calc(a - 1, c, d)
    ans_a = a-1 - calc(a-1,c,d)
    ans_b = b - calc(b,c,d)
    # print(b - a + 1 - ans)
    print(ans_b - ans_a)