#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>
#include <cassert>

using namespace std;
using ll = long long;

int main(){

    int X, n=0, x=0;
    cin >> X;
    vector<int> ans(1000, -1), a = {2,2,-1,-1,2,-1,-1};
    ans[0] = 0;
    for (int i=0; i<100; i++){
        for (int j=0; j<7; j++){
            n += a[j];
            x += abs(a[j]);
            if (ans[n] == -1) ans[n] = x;
        }
    }

    cout << ans[X] << endl;

    return 0;
}