#include<iostream>
#include<cmath>
using namespace std;

int main(){
    long long n;
    cin >> n;
    bool isPrime = (n%2 != 0);
    long long ans = !isPrime ? n/2 : 100000000001;
    for(long long i = 3; i <= sqrt(n); i++){
        if(n%i == 0){
            isPrime = false;
            ans = min(ans, min(i, n/i));
        }
    }

    cout << (isPrime ? n : ans) << endl;
    return 0;
}