#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <numeric>
#include <functional>
#include <cmath>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <sstream>
#include <string>

#define repd(i,a,b) for (int i=(a);i<(b);i++)
#define rep(i,n) repd(i,0,n)
#define var auto
#define mod 1000000007
#define inf 2147483647
#define nil -1
typedef long long ll;

using namespace std;

inline int input(){
    int a;
    cin >> a;
    return a;
}

template <typename T>
inline void output(T a, int p) {
    if(p){
        cout << fixed << setprecision(p)  << a << "\n";
    }
    else{
        cout << a << "\n";
    }
}

// end of template


int main() {
    cin.tie(0);
    // source code
    string s;
    cin >> s;
    if (s.size() >= 3) {
        output(8, 0);
        return 0;
    }
    stringstream sin;
    int num;
    sin << s;
    sin >> num;
    
    if (num == 4) output(3, 0);
    else if(num == 6) output(5, 0);
    else if(num == 8 || num == 9 || num == 10 || num == 15 || num == 16 || num == 22) output(7, 0);
    else if(num == 12) output(11, 0);
    else if(num == 14) output(13, 0);
    else if(num == 20) output(19, 0);
    else if(num == 21) output(20, 0);
    else output(8, 0);
    
    return 0;
}