#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=a;i<b;i++)

typedef long long ll;

int main()
{
	ll N; cin >> N;
	ll ans = N;
	rep(i, 2, sqrt(N)+1)
	{
		if (N % (ll)i == 0)
		{
			if (i == 2)
				ans = min(ans, N / (ll)i);
			else
				ans = min(ans, (ll)i);
		}
	}
	cout << ans << endl;
}