#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <complex>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <iomanip>
#include <assert.h>
#include <array>
#include <cstdio>
#include <cstring>
#include <random>
#include <functional>
#include <numeric>
#include <bitset>

using namespace std;

#define REP(i,a,b) for(int i=a;i<(int)b;i++)
#define rep(i,n) REP(i,0,n)
#define all(c) (c).begin(), (c).end()
#define zero(a) memset(a, 0, sizeof a)
#define minus(a) memset(a, -1, sizeof a)
#define minimize(a, x) a = std::min(a, x)
#define maximize(a, x) a = std::max(a, x)

typedef __int128_t ll;
int const inf = 1<<29;

namespace math {

ll mulmod(ll a, ll b, ll mod) {
  ll x = 0, y = a % mod;
  while(b > 0) {
    if(b & 1) {
      x = (x + y) % mod;
    }
    y = (y * 2) % mod;
    b /= 2;
  }
  return x % mod;
}

}

template<class value_type = long long> value_type mod_pow(value_type x, value_type n, value_type mo) { value_type ret = 1; while(n > 0) { if(n & 1) { ret = ret * x % mo; } x = x * x % mo; n >>= 1; } return ret; }

namespace math {
namespace prime {

bool miller_rabin(ll p,int iteration) {
  if(p < 2) { return false; }
  if (p != 2 && p % 2==0) { return false; }
  ll s = p - 1;
  while(s % 2 == 0) { s /= 2; }
  rep(_, iteration) {
    ll a = std::random_device()() % (p - 1) + 1, temp = s;  // これもうわかんねぇな
    ll mod = mod_pow<ll>(a, temp, p);
    while (temp != p - 1 && mod != 1 && mod != p - 1) {
      mod = mulmod(mod, mod, p);
      temp *= 2;
    }
    if (mod != p - 1 && temp % 2 == 0) { return false; }
  }
  return true;
}

}
}

typedef ll Int;
Int mulmod(Int a,Int n,Int Mod){
    Int res=0;
    while(n){
        if(n&1)res=(res+a)%Mod;
        a=(a+a)%Mod;
        n>>=1;
    }
    return res;
}

Int powmod(Int a,Int n,Int Mod){
    Int res=1;
    while(n){
        if(n&1)res=mulmod(res,a,Mod);
        a=mulmod(a,a,Mod);
        n>>=1;
    }
    return res;
}

bool miller_rabin(Int n){
    Int d=n-1,s=0;
    while(d%2==0){
        d/=2;
        s+=1;
    }
    for(int k=2;k<100;k++){
//        if(!prime[k])continue;
        Int a=k;
        if(powmod(a,d,n)!=1){
            bool b=true;
            for(Int r=0,_d=d;r<s;r++,_d<<=1){
                b&=(powmod(a,_d,n)!=n-1);
                //print(powmod(a,_d,n));
                if(powmod(a,_d,n)<0)cout<<"ERROR"<<endl;
            }
            if(b){return false;}
        }
    }
    return true;
}


map<ll, int> mp = {
  {4,3}, 
  {6,5}, 
  {8,7}, 
  {9,7}, 
  {10,7}, 
  {12,11}, 
  {14,13}, 
  {15,7}, 
  {16,7}, 
  {18,8}, 
  {20,19}, 
  {21,19}, 
  {22,7}, 
  {24,23}, 
  {25,23},
};

int main() {

  string s; cin >> s;
  ll N = 0;
  rep(i, s.size()) {
    N = N * 10;
    N = N + (s[i] - '0');
  }

  if(mp.find(N) != mp.end()) {
    cout << mp[N] << endl;
    exit(0);
  }

  if((N % 8 == 1) && math::prime::miller_rabin(N-8, 10000)) {
    cout << 14 << endl;
  }
  else {
    cout << 8 << endl;
  }

  return 0;
}