#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <math.h>
#include <cmath>
#include <limits.h>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <functional>
#include <stdio.h>
using namespace std;

long long MOD = 1000000007;

int main() {
    
    long long N;
    cin >> N;
    for ( long long a = 3; a*a <= N; a++ ) {
        if ( N%a == 0 ) { cout << a << endl; return 0; }
    }
    if ( N%2 == 0 ) { cout << N/2 << endl; }
    else { cout << N << endl; }
    
    
    return 0;
}