Problem:
Score : 100 points

Problem Statement

Takahashi wants to print a document with N pages double-sided, where two pages of data can be printed on one sheet of paper.

At least how many sheets of paper does he need?

Constraints

N is an integer.

1 \leq N \leq 100

Input

Input is given from Standard Input in the following format:

N

Output

Print the answer.

Sample Input 1

5

Sample Output 1

3

By printing the 1-st, 2-nd pages on the 1-st sheet, 3-rd and 4-th pages on the 2-nd sheet, and 5-th page on the 3-rd sheet, we can print all the data on 3 sheets of paper.

Sample Input 2

2

Sample Output 2

1

Sample Input 3

100

Sample Output 3

50

Solution in Rust (1.15.1) (judge verdict: Accepted)

use std::str::FromStr;
use std::io::{stdin, BufRead};

fn read<T: FromStr>() -> T {
    let mut s = String::new();
    let stdin = stdin();
    let mut input = stdin.lock();
    input.read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

fn read_vec<T: FromStr>() -> Vec<T> {
    read::<String>().split_whitespace()
        .map(|e| e.parse().ok().unwrap()).collect()
}

fn read_vec2<T: FromStr>(n: u32) -> Vec<Vec<T>> {
    (0..n).map(|_| read_vec()).collect()
}

pub struct Foo {
    ch: char
}

pub struct ParseCharError {
    kind: CharErrorKind,
}

impl ParseCharError {
    pub fn __description(&self) -> &str {
        match self.kind {
            CharErrorKind::EmptyString => "cannot parse char from empty string",
            CharErrorKind::TooManyChars => "too many characters in string",
        }
    }
}

enum CharErrorKind {
    EmptyString,
    TooManyChars,
}

impl FromStr for Foo {
    type Err = ParseCharError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let mut chars = s.chars();
        match (chars.next(), chars.next()) {
            (None, _) => Err(ParseCharError { kind: CharErrorKind::EmptyString }),
            (Some(c), None) => Ok(Foo { ch: c }),
            _ => Err(ParseCharError { kind: CharErrorKind::TooManyChars }),
        }
    }
}

fn main() {
    let n: u32 = read();
    println!("{}" , n / 2 + n % 2);
}