fn main() {
    let n = read::<i64>();
    if n % 2 == 0 {
        println!("{}", n / 2 + 1);
    } else {
        println!("1");
    }
}

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