#include <bits/stdc++.h>
using namespace std;
int main(void) {
  int sheets = 0;
  int N;
  cin >> N;
  if (N % 2 == 0) {
    sheets = (int)N / 2 + 1;
  } else {
    sheets = N / 2;
  }
  cout << sheets;
  return 0;
}
