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_mut, unused_variables, unused_assignments)]

macro_rules! input {
    ($($s:tt,$r:tt),*) => {
        let stdin = std::io::stdin();
        let mut buf = String::new();
        stdin.read_line(&mut buf).unwrap();
        let mut iter = buf.split_whitespace();
        $(let $s:$r = iter.next().unwrap().parse().unwrap();)*
    };
}

fn gcd(a:u64, b:u64) -> u64 {
    if 0 == b {return a;}
    return gcd(b, a % b);
}

fn lcm(a:u64, b:u64) -> u64 {
    return a / gcd(a, b) * b;
}

fn solve(n:u64, c:u64, d:u64) -> u64 {
    return n / c + n / d - n / lcm(c, d);
}

fn main() {
    input!(a,u64, b,u64, c,u64, d,u64);
    println!("{}", b - (a - 1) - (solve(b, c, d) - solve(a - 1, c, d)));
}