/* 
 *     Author:  srtry
 *     Created: 2025-05-31T10:22:10+09:00
 *     Coding:  utf-8-unix
 */

use proconio::input;
use std::io::{stdout,Write,BufWriter};
use std::collections::VecDeque;

fn main() {
    input!{
        n:usize
    }

    let out = stdout();
    let mut out = BufWriter::new(out.lock());
    
    // 3以上の約数のうち最小のものを計算すればいい
    let mut ans = n;
    if n%2==0 && n!=4{
        ans = n/2;
    }
    for factor in 3..=(n as f64).sqrt() as usize {
        if n%factor==0 {
            ans = factor;
            break;
        }
    }
    write!(out, "{}", ans).unwrap();
}