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)

use std::io;

fn read<T: std::str::FromStr>() -> Vec<T>{
    let mut te = String::new();
    io::stdin().read_line(&mut te).unwrap();
    te.trim().split_whitespace().map(|x| x.parse().ok().unwrap()).collect()
}

fn main() {
    let nums : Vec<i64> = read();
    let small = if nums[2] < nums[3] { nums[2] } else { nums[3] };
    let large = if nums[2] > nums[3] { nums[2] } else { nums[3] };
    let uc = small * large / p(small, large);
    let r = nums[1] - nums[0];
    let smalltotal = (nums[1] / small) - ((nums[0] - 1) / small); 
    let largetotal = (nums[1] / large) - ((nums[0] - 1) / large);
    let uctotal = (nums[1] / uc) - ((nums[0] - 1)/ uc);

    println!("{}", r - (smalltotal + largetotal - uctotal) + 1);
}


fn p(a: i64, b: i64) -> i64{
    let mut max : i64 = b;
    let mut min : i64 = a;
    let mut hold : i64 = 0;
    while max % min != 0 {
        hold = min;
        min = max % hold;
        max = hold;
    }
    min
}