#include<bits/stdc++.h>
#define REP(x,y,z) for(int x=y;x<=z;x++)
#define FORD(x,y,z) for(int x=y;x>=z;x--)
#define MSET(x,y) memset(x,y,sizeof(x))
#define FOR(x,y) for(__typeof(y.begin()) x=y.begin();x!=y.end();x++)
#define F first
#define S second
#define MP make_pair
#define PB push_back
#define SZ size()
#define M 
void RI(){}
template<typename... T>
void RI( int& head, T&... tail ) {
    scanf("%d",&head);
    RI(tail...);
}
using namespace std;
typedef long long LL;
LL n;
vector<LL> fac;
int main()
{
	int cnt;
	while(~scanf("%lld",&n))
	{
		fac.clear();
		REP(i,2,1000000)
		{
			cnt=0;
			while(n%i==0)
			{
				n /= i;
				cnt++;
			}

			if(cnt==1) fac.PB(i);
			else if(cnt>=2)
			{
				fac.PB(i);
				fac.PB(i);
			}
			
			if(n==1) break;
		}
		if(n!=1) fac.PB(n);

		LL ans=fac[0];
		if(ans==2)
		{
			if(fac[1]!=2) ans=fac[1];
			else
			{
				ans=4;
				FOR(i,fac) if(*i!=2) ans = min(ans, *i);
			}
		}
		printf("%lld\n",ans);
	}
	return 0;
}