template_cp 0.1.3

This crate contains some utilities for easier and faster access to input and output
Documentation 
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use std::{io, str};

pub struct Scanner<R> {
    reader: R,
    buf_str: Vec<u8>,
    buf_iter: str::SplitAsciiWhitespace<'static>,
}

impl<R: io::BufRead> Scanner<R> {
    pub fn new(reader: R) -> Self {
        Self {
            reader,
            buf_str: vec![],
            buf_iter: "".split_ascii_whitespace(),
        }
    }
    pub fn tok<T: str::FromStr>(&mut self) -> T {
        loop {
            if let Some(token) = self.buf_iter.next() {
                return token.parse().ok().expect("Failed parse");
            }
            self.buf_str.clear();
            self.reader
                .read_until(b'\n', &mut self.buf_str)
                .expect("Failed read");
            self.buf_iter = unsafe {
                let slice = str::from_utf8_unchecked(&self.buf_str);
                std::mem::transmute(slice.split_ascii_whitespace())
            }
        }
    }
}

fn main() {
    let mut scan = Scanner::new(io::stdin().lock());
    let mut out = io::BufWriter::new(io::stdout().lock());
    solve(&mut scan, &mut out);
}

fn solve<R: io::BufRead, W: io::Write>(scan: &mut Scanner<R>, out: &mut W) {
    let n: usize = scan.tok();
    writeln!(out, "{}", n).ok();
}