RT

#include<iostream>
#include<cstdio>
#include<cstring>

using namespace std;

int k,ans,s;
bool pe[30];

int main() {
	cin >> k;
	int kk = 2*k;
	for(int j = k+1; ;j++) {
		ans = 1,s = 0;
		int ss = 0;
		bool che = true;
		memset(pe,0,sizeof(pe));
		while(s < k) {
			if(ans == kk+1)
				ans = 1;
			if(pe[ans] == true) {
				ans++;
				continue;
			}
			ss++;
			if(ss == j) {
				s++;
				ss = 0;
				pe[ans] = true;
				if(ans >=1 && ans <=k) {
					che = false;
					break;
				}
			}
			ans++;
		}
		if(che == true) {
			cout << j;
			break;
		}
	}
	
	return 0;
}