#include <bits/stdc++.h>
using namespace std;
int main(){
   int n,h;
   cin>>n;
   if (n%2==0){
    h=n/2+1+n/2;
   }
       
   else {
    h=n-(n/2-0.5);
   }  
   cout<<h<<endl;
}
/**************************************************************
	Problem: 1558
	User: xiaojingxuan
	Language: C++
	Result: Accepted
	Time:42 ms
	Memory:2072 kb
****************************************************************/