#include "bits/stdc++.h"
#define int long long
using namespace std;
using ll = long long;
//using P = pair<ll, pair<ll, ll>>;
const ll INF = (1LL << 61);
ll mod = 1000000007;
struct mint {
	ll x; // typedef long long ll;
	mint(ll x = 0) :x((x%mod + mod) % mod) {}
	mint operator-() const { return mint(-x); }
	mint& operator+=(const mint a) {
		if ((x += a.x) >= mod) x -= mod;
		return *this;
	}
	mint& operator-=(const mint a) {
		if ((x += mod - a.x) >= mod) x -= mod;
		return *this;
	}
	mint& operator*=(const mint a) {
		(x *= a.x) %= mod;
		return *this;
	}
	mint operator+(const mint a) const {
		mint res(*this);
		return res += a;
	}
	mint operator-(const mint a) const {
		mint res(*this);
		return res -= a;
	}
	mint operator*(const mint a) const {
		mint res(*this);
		return res *= a;
	}
	mint pow(ll t) const {
		if (!t) return 1;
		mint a = pow(t >> 1);
		a *= a;
		if (t & 1) a *= *this;
		return a;
	}

	// for prime mod
	mint inv() const {
		return pow(mod - 2);
	}
	mint& operator/=(const mint a) {
		return (*this) *= a.inv();
	}
	mint operator/(const mint a) const {
		mint res(*this);
		return res /= a;
	}
};
istream& operator>>(istream& is, mint& a) { return is >> a.x; }
ostream& operator<<(ostream& os, const mint& a) { return os << a.x; }
int beki[40];
signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int N; cin >> N;
	if (N == 1)cout << 1 << endl;
	else if (N == 2 || N == 3)cout << 2 << endl;
	else {
		for (int x = max(1LL, N / 2 - 1000); x <= N / 2 + 10000; x++) {
			if ((N - 1) / x <= 2) {
				cout << x << endl; return 0;
			}
		}
		assert(N == -1);
	}

	return 0;
}