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 (1.15.1) (judge verdict: Accepted)

#[allow(unused_macros)]
macro_rules! get {
    ([$t:ty] ; $n:expr) => {
        (0..$n)
        .map(|_| get!([$t])).collect::<Vec<_>>()
    };
    ($($t:ty),+ ; $n:expr) => {
        (0..$n).map(|_| get!($($t),+)).collect::<Vec<_>>()
    };
    ([$t:ty]) => {
        rl().split_whitespace()
        .map(|x| x.parse().unwrap())
        .collect::<Vec<$t>>()
    };
    ($t:ty) => {
        rl().parse::<$t>().unwrap()
    };
    ($($t:ty),*) => {
        {
            let line =rl();
            let mut iter = line.split_whitespace();
            ($(iter.next().unwrap().parse::<$t>().unwrap()),*)
        }
    };
}
fn rl() -> String {
    let mut line = String::new();
    std::io::stdin().read_line(&mut line).unwrap();
    line.trim().to_string()
}

fn gcd(a: usize, b: usize) -> usize {
    let mut a = a;
    let mut b = b;
    while b != 0 {
        let r = b;
        b = a % b;
        a = r;
    }
    a
}

fn lcm(a: usize, b: usize) -> usize {
    return a / gcd(a, b) * b;
}

fn main() {
    let (a, b, c, d) = get!(usize, usize, usize, usize);
    let rc = b / c - (a - 1) / c;
    let rd = b / d - (a - 1) / d;
    // eprintln!("rc: {}, rd: {}", rc, rd);
    let l = lcm(c, d);
    let rl = b / l - (a - 1) / l;
    // eprintln!("l: {}, rl: {}", l, rl);
    println!("{}", (b - a + 1) + rl - rc - rd);
}