#include<iostream>
#include<vector>
#include<cmath>
#include<algorithm>

std::vector<long long> divisor(long long n){
    std::vector<long long> v;
    v.push_back(n);
    long long s = sqrt(n);
    for(long long i = 2; i <= s; i++){
        if(n % i == 0){
            v.push_back(i);
            // 平方数ではない
            if(n / i != i){
                v.push_back(n / i);
            }
        }
    }
    return v;
}

int main(){
    long long n;
    std::cin >> n;

    std::vector<long long> v = divisor(n);
    std::sort(v.begin(), v.end());
    if(v.front() == 2) v.erase(v.begin());
    std::cout << v.front() << std::endl;
    return 0;
}