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::gcd;
#[allow(unused_imports)]
use proconio::marker::{Bytes, Chars, Usize1};
use proconio::{fastout, input};
#[fastout]
fn main() {
    input! {
        a: u64,
        b: u64,
        c: u64,
        d: u64,
    }
    let gcd = gcd(c, d);
    let lcm = c * d / gcd;
    let b_ans = b - b / c - b / d + b / lcm;
    let a_ans = (a - 1) - (a - 1) / c - (a - 1) / d + (a - 1) / lcm;
    let ans = b_ans - a_ans;
    println!("{:?}", ans);
}