/*
TASK:minitime
LANG:C++
*/
#include<iostream>
using namespace std;
int main()
{
    int k,i,m,n,p=0,mi;
    cin>>k;
    mi=k*2;
    for(i=1;i<=k;i++)
    {
                     if(k%i==0)n=k/i;
                     else n=(k/i)+1;
                     m=i;
                     if(m>1)p+=m;
                     if(n>1)p+=n;
                     if(p<mi)mi=p;
                     p=0;
    }
    cout<<mi<<endl;
    return 0;
}
