#include <algorithm>
#include <bits/stdc++.h>
#include <atcoder/all>
        
using namespace std;
using namespace atcoder;
using mint = modint998244353;
using ll=long long;
 
bool chmin(ll& a, ll b){ if(a > b){ a = b; return 1; } return 0; }
bool chmax(int& a, int b){ if(a < b){ a = b; return 1; } return 0; }
constexpr ll TEN(int n) { return (n == 0) ? 1 : 10 * TEN(n - 1); }
const ll MOD = 998244353LL;
using pll = pair<int, int>;
const int INF = 1e7;

vector<int> sieve(int X) {
    vector<bool> cs(X+1, true);
    for (int i = 2; i*i <= X; ++i) {
        if (cs[i]) {
            for (int j = i*i; j <= X; j+=i) cs[j] = false;
        }
    }
    vector<int> ans;
    for (int i = 2; i <= X; ++i) if (cs[i]) ans.push_back(i);
    return ans;
}

ll gcd(ll a, ll b) {
    if (b==0) return a;
    return gcd(b, a%b);
}


int main() {
    ll N;
    cin >> N;
    int ans = (N&1) ? 1 : 1+N/2;
    cout << ans << endl;
    return 0;
}