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)

#[macro_use]
mod utils {
    macro_rules! input {
        ($($r:tt)*) => {
            let stdin = std::io::stdin();
            let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
            let mut next = move || -> String{
                bytes
                    .by_ref()
                    .map(|r|r.unwrap() as char)
                    .skip_while(|c|c.is_whitespace())
                    .take_while(|c|!c.is_whitespace())
                    .collect()
            };
            input_inner!{next, $($r)*}
        };
    }
    macro_rules! input_inner {
        ($next:expr) => {};
        ($iter:expr, ) => {};
 
        ($next:expr, $var:ident : $t:tt $($r:tt)*) => {
            let $var = read_value!($next, $t);
            input_inner!{$next $($r)*}
        };
        ($next:expr, mut $var:ident : $t:tt $($r:tt)*) => {
            let mut $var = read_value!($next, $t);
            input_inner!{$next $($r)*}
        };
    }
    macro_rules! read_value {
        ($next:expr, ( $($t:tt),* )) => {
            ( $(read_value!($next, $t)),* )
        };
        ($next:expr, [ $t:tt ; $len:expr ]) => {
            (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
        };
        ($next:expr, chars) => {
            read_value!($next, String).chars().collect::<Vec<char>>()
        };
        ($next:expr, usize1) => {
            read_value!($next, usize) - 1
        };
        ($next:expr, $t:ty) => {
            $next().parse::<$t>().expect("Parse error")
        };
    }
}


fn main(){
    input!{
        s: i32,
    }
    if s % 2 == 0 {
        println!("{}", s / 2);
    }else {
        println!("{}", (s / 2) + 1);
    }

}