fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();

    let judge = |p| {
        if p <= 1 { return false }
        let x = n % p;
        let mut y = n;
        while y > 0 {
            if y % p != x { return false }
            y /= p;
        }
        true
    };
    let mut ans: usize = n - 1;
    if n == 2 { ans = 3 }
    else { 
        for i in (1..).take_while(|x| x * x <= n) {
            if judge(i) {
                ans = i;
                break;
            }
            if n % i == 0 {
                let p = n / i - 1;
                if p > 1 && judge(p) { ans =  p }
            }
        }
    };
    println!("{}", ans);
}