#include <iostream>
#include <string>
#include <cstdlib>
#include <algorithm>
using namespace std;

int table[50][50];

bool solve(int i, int j) {
	if(!(table[i][j]+1))
		return false;
	if(!(table[i][j]-1))
		return true;
	table[i][j]=-1;
	bool res = false;
	const int dxy[] = {1,0,-1,0,1};
	for(int k = 0; k < 4; k++) {
		res |= solve(i+dxy[k],j+dxy[k+1]);
	}
	return res;
}

int main() {
	string n;
	cin >> n;
	if(n.size() >= 3 || atoi(n.c_str()) > 28) {
		cout << 8 << endl;
		return 0;
	}

	int N = atoi(n.c_str());
	int w = 1;
	while(1) {
		for(int i = 0; i < 50; i++)
			for(int j = 0; j < 50; j++)
				table[i][j] = -1;
		for(int i = 0; i < N; i++) {
			table[i/w + 1][i%w + 1] = 0;
			bool p = true;
			for(int j = 2; j < i+1; j++) {
				p &= (i+1)%j != 0;
			}
			if(p&&i)
				table[i/w+1][i%w+1] = -1;
		}
		table[(N-1)/w+1][(N-1)%w+1] = 1;
		if(solve(1,1))
			break;
		w++;
	}
	cout << w << endl;
}