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 Rust (1.42.0) (judge verdict: Accepted)

use num::integer::lcm;
use proconio::{fastout, input};

#[fastout]
fn main() {
    input! {
        a: i64,
        b: i64,
        c: i64,
        d: i64,
    }

    let a = a - 1;
    let ans = (b - b / c - b / d + b / lcm(c, d)) - (a - a / c - a / d + a / lcm(c, d));

    println!("{}", ans);
}