#include <bits/stdc++.h>
#define syosu(x) fixed<<setprecision(x)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
typedef pair<double,double> pdd;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<string> vs;
typedef vector<P> vp;
typedef vector<vp> vvp;
typedef vector<pll> vpll;
typedef pair<P,int> pip;
typedef vector<pip> vip;
const int inf=1<<30;
const ll INF=1ll<<60;
const double pi=acos(-1);
const double eps=1e-8;
const ull mod=1e9+7;
const int dx[4]={-1,0,1,0},dy[4]={0,-1,0,1};

int h,w=2,n;
string s;
vvi a;

void dfs(int x,int y){
	a[x][y]=2;
	for(int i=0;i<4;i++){
		int X=x+dx[i],Y=y+dy[i];
		if(X>=0&&X<h&&Y>=0&&Y<w){
			bool B=0;
			int A=a[X][Y];
			for(int j=2;j*j<=A;j++) if(A%j==0) B=1;
			if(B) dfs(X,Y);
		}
	}
}

int main(){
	cin>>s;
	if(s.size()>2) cout<<8<<endl;
	else{
		n=atoi(s.c_str());
		while(1){
			h=(n+w-1)/w;
			a=vvi(h,vi(w,2));
			for(int i=0;i<n;i++) a[i/w][i%w]=i+1;
			dfs(0,0);
			if(a[(n-1)/w][(n-1)%w]==2) break;
			w++;
		}
		cout<<w<<endl;
	}
}