# include <iostream>
# include <cmath>
using namespace std;
int main () {
   long long a,c;
   double b;
   cin>>a;
   b=sqrt(a);
   c=b;
   if (c!=b) c++;
   b=round(b);
   a=a-b-c;
   a=a*2+b*3+c*3;
   cout<<a<<endl;
   return 0;
}