#include <bits/stdc++.h>
using namespace std;
typedef long long LL;

LL Cxiv_Dxiv(LL n){
    LL res=n;
    if(n%2==0&&n/2>2)res=n/2;
    for(LL i = 3; i*i <= n; i++)if(n%i==0)res=min(res,min(i,n/i));
    return res;
}
int main() {
    LL N;
    cin>>N;
    cout<<Cxiv_Dxiv(N)<<endl;
    return 0;
}