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: Wrong Answer)

use whiteread::parse_line;

fn main() {
    let (a, b, c, d): (usize, usize, usize, usize) = parse_line().unwrap();
    let cd: usize = c*d;

    let mut cc = 0;
    for _ in (a..b).step_by(c) {
        cc += 1;
    }

    let mut dc = 0;
    for _ in (a..b).step_by(d) {
        dc += 1;
    }

    let mut cdc = 0;
    for _ in (a..b).step_by(cd) {
        cdc += 1;
    }

    println!("{}", b - a + 1 - cc - dc + cdc);
}