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)

fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().split_whitespace().map(|e| e.parse().ok().unwrap()).collect()
}

fn read_vec2<T: std::str::FromStr>(n: u32) -> Vec<Vec<T>> {
    let mut v2 = Vec::new();
    for _ in 0..n {
        let mut s = String::new();
        std::io::stdin().read_line(&mut s).ok();
        let v = s.trim().split_whitespace()
            .map(|e| e.parse().ok().unwrap()).collect();
        v2.push(v);
    }
    v2
}

fn gcd(a:i128, b:i128) -> i128 {

    let mut a = a;
    let mut b = b;
    let mut tmp = 0;
    if a < b {
        tmp = a;
        a = b;
        b = tmp;
    }

    let mut r = a % b;
    while r !=0 {
        a = b;
        b = r;
        r = a % b;
    }

    b
}

fn canti() {

    let data: Vec<i128> = read_vec();

    let lcm = (data[2]/gcd(data[2],data[3])) * data[3];
    //println!("lcm {}", lcm);
    let b =  data[1]/data[2] + data[1]/data[3] - data[1]/lcm ;
    //println!("a {}", b);
    let a =(data[0]-1)/data[2] + (data[0]-1)/data[3] - (data[0]-1)/lcm;
    //println!("b {}", a);


    println!("{}", (data[1] - data[0] + 1) - (b-a));
}

fn main() {
    canti();
}