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)

// This code is generated by [cargo-atcoder](https://github.com/tanakh/cargo-atcoder)
// Original source code:
/*
#[allow(unused_macros)]
macro_rules! debug {
	($($a:expr),*) => {
		println!(concat!($(stringify!($a), " = {:?}, "),*), $($a),*);
	}
}

#[allow(dead_code)]
const MOD: usize = 1e9 as usize + 7;

extern crate num_integer;
use num_integer::lcm;

fn count(n: u128, c: u128, d: u128, cd: u128) -> u128 {
	n - n / c - n / d + n / cd
}

fn main() {
	let (r, w) = (std::io::stdin(), std::io::stdout());
	let mut sc = IO::new(r.lock(), w.lock());

	let a: u128 = sc.read();
	let b: u128 = sc.read();
	let c: u128 = sc.read();
	let d: u128 = sc.read();

	let cd = lcm(c, d);
	println!("{}", count(b, c, d, cd) - count(a - 1, c, d, cd));
}

pub struct IO<R, W: std::io::Write>(R, std::io::BufWriter<W>);

impl<R: std::io::Read, W: std::io::Write> IO<R, W> {
	pub fn new(r: R, w: W) -> IO<R, W> {
		IO(r, std::io::BufWriter::new(w))
	}
	pub fn write<S: std::ops::Deref<Target = str>>(&mut self, s: S) {
		use std::io::Write;
		self.1.write(s.as_bytes()).unwrap();
	}
	pub fn read<T: std::str::FromStr>(&mut self) -> T {
		use std::io::Read;
		let buf = self
			.0
			.by_ref()
			.bytes()
			.map(|b| b.unwrap())
			.skip_while(|&b| b == b' ' || b == b'\n' || b == b'\r' || b == b'\t')
			.take_while(|&b| b != b' ' && b != b'\n' && b != b'\r' && b != b'\t')
			.collect::<Vec<_>>();
		unsafe { std::str::from_utf8_unchecked(&buf) }
			.parse()
			.ok()
			.expect("Parse error.")
	}
	pub fn read_vec<T: std::str::FromStr>(&mut self, n: usize) -> Vec<T> {
		(0..n).map(|_| self.read()).collect()
	}
	pub fn read_chars(&mut self) -> Vec<char> {
		self.read::<String>().chars().collect()
	}
	pub fn read_pairs<T: std::str::FromStr>(&mut self, n: usize) -> Vec<(T, T)> {
		(0..n)
			.map(|_| (self.read::<T>(), self.read::<T>()))
			.collect::<Vec<(T, T)>>()
	}
	pub fn read_matrix<T: std::str::FromStr>(&mut self, n: usize, m: usize) -> Vec<Vec<T>> {
		(0..n)
			.map(|_| (0..m).map(|_| self.read()).collect())
			.collect()
	}
}
*/

fn main() {
    let exe = "/tmp/bin9C101C1D";
    std::io::Write::write_all(&mut std::fs::File::create(exe).unwrap(), &decode(BIN)).unwrap();
    std::fs::set_permissions(exe, std::os::unix::fs::PermissionsExt::from_mode(0o755)).unwrap();
    std::process::exit(std::process::Command::new(exe).status().unwrap().code().unwrap())
}

fn decode(v: &str) -> Vec<u8> {
    let mut ret = vec![];
    let mut buf = 0;
    let mut tbl = vec![64; 256];
    for i in 0..64 { tbl[TBL[i] as usize] = i as u8; }
    for (i, c) in v.bytes().filter_map(|c| { let c = tbl[c as usize]; if c < 64 { Some(c) } else { None } }).enumerate() {
        match i % 4 {
            0 => buf = c << 2,
            1 => { ret.push(buf | c >> 4); buf = c << 4; }
            2 => { ret.push(buf | c >> 2); buf = c << 6; }
            3 => ret.push(buf | c),
            _ => unreachable!(),
        }
    }
    ret
}

const TBL: &'static [u8] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
const BIN: &'static str = "<base64-encoded ELF executable removed>";