using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Numerics;
using BI=System.Numerics.BigInteger;

class TEST{
	static void Main(){
		Sol mySol =new Sol();
		mySol.Solve();
	}
}

class Sol{
	public void Solve(){
		
		
		int ans=0;
		int N2=0;
		if(N<100){
			N2=(int)N;
			switch(N2){
				case 4:	ans=3;break;
				case 6:	ans=5;break;
				case 8:	ans=7;break;
				case 9:	ans=7;break;
				case 10:	ans=7;break;
				case 15:	ans=7;break;
				case 16:	ans=7;break;
				case 22:	ans=7;break;
				case 33:	ans=8;break;
				case 57:	ans=8;break;
				case 65:	ans=8;break;
				case 12:	ans=11;break;
				case 14:	ans=13;break;
				case 20:	ans=19;break;
				case 21:	ans=19;break;
				case 24:	ans=23;break;
				case 25:	ans=23;break;
				default:
					if(N%8==1){
						ans=14;
					}else{
						ans=8;
					}break;
			}
			Console.WriteLine(ans);
			return;
		}
		
		Console.WriteLine((N%8==1 && IsPrime(N-8))?14:8);
		
	}
	String S;
	BI N;
	public Sol(){
		S=rs();
		N=BI.Parse(S);
	}

	static bool IsPrime(BI x){
		if(x==2)return true;
		if((x==1) || (x&1)==0)return false;
		if(x<(BI)1e12){
			for(BI t=2;t*t<=x;t++){
				if(x%t==0)return false;
			}
			return true;
		}
		return MillerRabinTest(x);
	}
	
	static bool MillerRabinTest(BI n){
		int rep=20;
		BI d=n-1;
		// (n-1)=2^s*d
		while((d&1)==0)d>>=1;
		
		var rnd=new Xor128();
		BI a=1+((BI)rnd.Next())%(n-2);
		
		while(rep>0){
			rep--;
			a=1+((BI)rnd.Next()*a)%(n-2);
			BI t=d;
			BI y=ModPowBI(a,t,n);
			while(t!=(n-1) && y!=1 && y!=n-1){
				y=y*y%n;
				t<<=1;
			}
			if(y!=(n-1) && (t&1)==0)return false;
		}
		return true;
	}
	
	static BI ModPowBI(BI a,BI t,BI mod){
		BI ret=1;
		while(t>0){
			if((t&1)==1){ret*=a;ret%=mod;};
			a=a*a;a%=mod;
			t>>=1;
		}
		return ret;
	}
	


	static String rs(){return Console.ReadLine();}
	static int ri(){return int.Parse(Console.ReadLine());}
	static long rl(){return long.Parse(Console.ReadLine());}
	static double rd(){return double.Parse(Console.ReadLine());}
	static String[] rsa(){return Console.ReadLine().Split(' ');}
	static int[] ria(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>int.Parse(e));}
	static long[] rla(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>long.Parse(e));}
	static double[] rda(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>double.Parse(e));}
}


class Xor128{
	static uint x = 123456789;
	static uint y = 362436069;
	static uint z = 521288629;
	static uint w = 88675123; 
	uint t;
	
	public Xor128(){
	}
	
	public Xor128(uint seed){
		z ^= seed;
		z ^= z >> 21; z ^= z << 35; z ^= z >> 4;
	}
	
	
	public uint Next(){
		t = x ^ (x << 11);
		x = y; y = z; z = w;
		return w = (w ^ (w >> 19)) ^ (t ^ (t >> 8));
	}
	public int Next(int ul){
		return NextI(0,ul-1);
	}
	public int NextI(int from,int to){
		int mod=to-from+1;
		int ret=(int)(Next()%mod);
		return ret+from;
	}
}