Problem:
Score : 100 points

Problem Statement

How many multiples of d are there among the integers between L and R (inclusive)?

Constraints

All values in input are integers.

1 \leq L \leq R \leq 100

1 \leq d \leq 100

Input

Input is given from Standard Input in the following format:

L R d

Output

Print the number of multiples of d among the integers between L and R (inclusive).

Sample Input 1

5 10 2

Sample Output 1

3

Among the integers between 5 and 10, there are three multiples of 2: 6, 8, and 10.

Sample Input 2

6 20 7

Sample Output 2

2

Among the integers between 6 and 20, there are two multiples of 7: 7 and 14.

Sample Input 3

1 100 1

Sample Output 3

100

Solution in Rust (1.42.0) (judge verdict: Accepted)

fn main(){
    let lrd: Vec<u32> = read_vec();
    let l = lrd[0];
    let r = lrd[1];
    let d = lrd[2];
    
    println!("{}", r / d - (l - 1) / d);

}

#[allow(dead_code)]
fn read_vec<T>() -> Vec<T>
where T: std::str::FromStr,
      T::Err: std::fmt::Debug
{
    let mut buf = String::new();
    std::io::stdin().read_line(&mut buf).expect("failed to read");
    buf.split_whitespace().map(|e| e.parse().unwrap()).collect()
}