#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cmath>

using namespace std;

int main()
{int n,j,leap=0;
 cin>>n;
 for (int i=floor(sqrt(n));i>1;i--)
    {if (n%i==0)
        {j=n/i;
         leap=0;
         for (int k=2;k<=sqrt(j);k++)
            if (j%k==0)
                {leap=1;break;}
         if (leap==0)
            {cout<<j;break;}            
        }
    }
 return 0;
}