#include<bits/stdc++.h>
using namespace std;
queue<int> q;
int n, cnt, c;
bool f(int m) {
	while(q.size()){
		q.pop();
	}
	for (int i = 1; i <= 2 * n; i++) {
		q.push(i);
	}
	while (q.size()) {
		int x = q.front();
		q.pop();
		cnt++;
		if (cnt % m == 0) {
			if (x > n) {
				c++;
			}
			if (x == 1) {
				if (c == x) {
					return 1;
				} else {
					return 0;
				}
			}
		} else {
			q.push(x);
		}
	}
}
int main() {
	cin >> n;

	int i = 2;
	while (1) {
		if (f(i) == 1) {
			break;
		}
		i++;
	}
	cout << i;
}