#include <iostream>
#include <vector>
#include <algorithm>
#include <atcoder/modint>
using namespace std;
using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
#define rep(i,n) for(int i=0; i<(int)(n); i++)

using m32 = atcoder::modint998244353;

int main(){
    int N; cin >> N;
    int res = 0;
    for(int i=0; N!=0; i++){
        if(i % 7 == 6) N += 6;
        res++;
        N--;
    }
    cout << res << endl;
    return 0;
}

struct ios_do_not_sync{
    ios_do_not_sync(){
        std::ios::sync_with_stdio(false);
        std::cin.tie(nullptr);
    }
} ios_do_not_sync_instance;