#include <bits/stdc++.h>
#define NIL (-1)
#define ll long long
using namespace std;
const int64_t MOD = 1e9 + 7;
const int INF = INT_MAX;
const double PI = acos(-1.0);

int main() {
	int N;
	cin >> N;
	cout << (N & 1 ? 1 : 1+N/2) << endl;
}