// Slower C++ solution:
#include <cstdio>

#include <cstdlib>

#include <cstring>

#include <iostream>

#include <algorithm>

typedef long long ll;

#define rep(i, a, b) for (int i = a; i <= b; ++ i)

const ll inf = 1000000000000000007LL;

using namespace std;

ll w[10][10], ans[10][10], tmp[10][10], m;

bool solve(ll n) {

	rep(i, 1, 6) rep(j, 1, 6) w[i][j] = - inf;

	rep(i, 1, 6) rep(j, 1, 6) if (i != j && i + j != 7) w[j][i] = i;

	bool flg = true;

	for ( ; n; n /= 2) {

		if (n & 1LL) {

			if (flg) {

				memcpy(ans, w, sizeof(w));

				flg = false;

			} else {

				rep(i, 1, 6) rep(j, 1, 6) tmp[i][j] = - inf;

				rep(i, 1, 6) rep(j, 1, 6) rep(k, 1, 6) 

					tmp[i][j] = max(tmp[i][j], ans[i][k] + w[k][j]);

				memcpy(ans, tmp, sizeof(tmp));

			}

		}

		rep(i, 1, 6) rep(j, 1, 6) tmp[i][j] = - inf;

		rep(i, 1, 6) rep(j, 1, 6) rep(k, 1, 6)

			tmp[i][j] = max(tmp[i][j], w[i][k] + w[k][j]);

		memcpy(w, tmp, sizeof(tmp));

	}

	ll mx = - inf;

	rep(i, 1, 6) rep(j, 1, 6) mx = max(mx, ans[i][j]);

	return (mx >= m);

}

int main() {

	scanf("%lld", &m);

	ll l = 1, r = inf, ans;

	for ( ; l <= r; ) {

		ll mid = (l + r) / 2;

		if (solve(mid)) ans = mid, r = mid - 1;

			else l = mid + 1;

	}

	printf("%lld\n", ans); 

	return 0;

}

// Faster C++ solution for the same problem (measured speedup: 1.5230475166282418x):
/**

    OJ :

    Program Code :

    Md. Mujahedul Azad (Turin)

    Hajee Mohammad Danesh Science & Technology University

**/



#include<bits/stdc++.h>

using namespace std;



#define pi              2*acos(0.0)

#define all(v)          v.begin(),v.end()

#define ff              first

#define se              second

#define pb              push_back

#define mp              make_pair

#define Sort(a)         sort(all(a))

#define RSort(a)        Sort(a), reverse(all(a))

#define sz(x)           (int)x.size()

#define max3(a,b,c)     max(a, max(b, c))

#define min3(a,b,c)     min(a, min(b, c))

#define maxall(v)       *max_element(all(v))

#define minall(v)       *min_element(all(v))

#define sq(a)           ((a) * (a))

#define abs(x)          (((x)<0)?-(x):(x))

#define precision(x)    cout << setprecision(x) << fixed

#define mem(a,v)        memset(a, v, sizeof(a))

#define fillAra(a,n,v)  fill(a, a+n, v)

#define fillVec(a, v)   fill(all(a), v)

#define countOne(a)     __builtin_popcount(a)

#define parity(a)       __builtin_parity(a)

#define btz(a)          __builtin_ctz(a)

#define gf              << ' ' <<

#define nl              << '\n'

#define cinIg           cin.sync(); cin.get()

#define FasterIO        ios_base::sync_with_stdio(false);cin.tie(NULL)

#define TestCases       int cases, tc; sfi(tc); for(cases=1; cases<=tc; cases++)

#define TestCasespp     int cases, tc; cin>>tc; for(cases=1; cases<=tc; cases++)

#define un(a)           Sort(a), (a).erase(unique(all(a)),a.end())

#define common(a,b)     Sort(a), Sort(b), a.erase(set_intersection(all(a), all(b), a.begin()), a.end())

#define uncommon(a,b)   Sort(a), Sort(b), a.erase(set_symmetric_difference(all(a), all(b), a.begin()), a.end())



/**------- ShortCuts----------*/

typedef long long             ll;

typedef unsigned long long    ull;

typedef double                db;

typedef long double           ldb;

typedef pair<int, int>        pii;

typedef pair<ll, ll>          pll;

typedef pair<int, pii>        iii;

typedef vector<int>           vi;

typedef vector<ll>            vl;

typedef vector<pii>           vii;

typedef vector<iii>           viii;

typedef vector<vi>            vvi;

typedef map<int, int>         mapii;

typedef map<int, bool>        mapib;

typedef map<int, string>      mapis;

typedef set<int>              seti;



/**------- Char Chk----------*/

inline bool isLow(char ch){if(ch>='a' && ch<='z') return true; return false;}

inline bool isUpp(char ch){if(ch>='A' && ch<='Z') return true; return false;}

inline bool isDig(char ch){if(ch>='0' && ch<='9') return true; return false;}



/**------- Double Chk----------*/

inline bool are_equal(db a, db b){return fabs(a-b)<numeric_limits<db>::epsilon();}

inline bool greater_than(db a, db b){return (a-b) > ((fabs(a)<fabs(b)?fabs(b):fabs(a)) * numeric_limits<db>::epsilon());}

inline bool less_than(db a, db b){return (b-a) > ((fabs(a)<fabs(b)?fabs(b):fabs(a)) * numeric_limits<db>::epsilon());}



/**------- Functions ---------*/

template<typename T> string toString(T x){stringstream ss; ss<<x; return ss.str();}

template<typename T> T SOD(T n){__typeof(n) sum=0, i=1; for(; i*i<=n; i++) sum += (n%i)?0:((sq(i)==n)?i:i+n/i); return sum;}

template<typename T> T stringToT(string s, T a){T p; istringstream ss(s); ss>>p; return p;}



template<typename T>ostream& operator << (ostream& os, const vector<T> &v){os << "["; for(int i=0; i<v.size(); i++){ os << v[i]; if(i != sz(v)-1) os << ", ";} os << "]"; return os;}

template<typename T>ostream& operator << (ostream& os, const set<T> &v){ os << "["; for(auto it : v){os << it;if(it != *v.rbegin())os << ", ";}os << "]";return os;}

template<typename T, typename S> ostream& operator << (ostream& os, const map<T, S> &v){for(auto it : v) os << it.ff << " : " << it.se nl; return os;}

template<typename T, typename S> ostream& operator << (ostream& os, const pair<T, S> &v){os << "(" << v.ff << ", " << v.se << ")";return os;}



ll power(ll a, ll b){ll res = 1; while(b){if(b & 1) res *= a; a = sq(a); b >>= 1;} return res;}

ll bigmod(ll a, ll b, ll m) {ll res = 1; while(b) { if(b & 1) { res = ( (res % m) * (a % m) ) %m ; } a= ((a%m) * (a%m)) %m; b >>= 1; } return res; }

ll modInverse(ll a, ll m) {return bigmod(a,m-2,m);}



/**------- Scanf----------*/

#define sf                 scanf

#define sfi(a)             scanf("%d", &a)

#define sfc(a)             scanf("%c", &a)

#define sfl(a)             scanf("%lld", &a)

#define sfu(a)             scanf("%llu", &a)

#define sfs(a)             scanf("%s", a)

#define sfd(a)             scanf("%lf", &a)

#define sfii(a, b)         scanf("%d %d", &a, &b)

#define sfll(a, b)         scanf("%lld %lld", &a, &b)

#define sfuu(a, b)         scanf("%llu %llu", &a, &b)

#define sfdd(a, b)         scanf("%lf %lf", &a, &b)

#define sfiii(a, b, c)     scanf("%d %d %d", &a, &b, &c)

#define sflll(a, b, c)     scanf("%lld %lld %lld", &a, &b, &c)

#define sfuuu(a, b, c)     scanf("%llu %llu %llu", &a, &b, &c)

#define sfddd(a, b, c)     scanf("%lf %lf %lf", &a, &b, &c)



/**------- Printf----------*/

#define pf                 printf

#define pfig(a)            pf("%d ", a)

#define pfgap              pf(" ")

#define pfi(a)             printf("%d\n", a)

#define pfc(a)             printf("%c\n", a)

#define pfl(a)             printf("%lld\n", a)

#define pfu(a)             printf("%llu\n", a)

#define pfs(a)             printf("%s\n", a)

#define pfd(a)             printf("%.2lf\n", a)

#define pfii(a, b)         printf("%d %d\n", a, b)

#define pfll(a, b)         printf("%lld %lld\n", a, b)

#define pfuu(a, b)         printf("%llu %llu\n", a, b)

#define pfdd(a, b)         printf("%.2lf %.2lf\n", a, b)

#define pfiii(a, b, c)     printf("%d %d %d\n", a, b, c)

#define pflll(a, b, c)     printf("%lld %lld %lld\n", a, b, c)

#define pfuuu(a, b, c)     printf("%llu %llu %llu\n", a, b, c)

#define pfddd(a, b, c)     printf("%.2lf %.2lf %.2lf\n", a, b, c)

#define pnl                printf("\n")



/**--------File------------*/

#define output             freopen("output.txt","w",stdout)

#define input              freopen("input.txt","r",stdin)

#define inOut              input, output

#define Case               printf("Case %d: ", cases)

#define Casepp             cout << "Case " << cases << ": "



/**--------Constant------------*/

#define mx2                101

#define mx3                1001

#define mx4                10001

#define mx5                100001

#define mx6                1000001

#define INF                0x3f3f3f3f

#define eps                1e-8



/**--------Loops--------------*/

#define frab(i, a, b)      for(__typeof(b) i=(a); i<=(b); i++)

#define fr0(i, n)          frab(i, 0, n-1)

#define fr1(i, n)          frab(i, 1, n)

#define rfrab(i, a, b)     for(__typeof(b) i=(b); i>=a; i--)

#define rfr0(i, n)         rfrab(i, (n)-1, 0)

#define rfr1(i, n)         rfrab(i, n, 1)

#define frabv(i, a, b, v)  for(__typeof(b) i=(a); i<=(b); i+=v)

#define rfrabv(i, a, b, v) for(__typeof(b) i=(b); i>=a; i-=v)

#define frstl(i, s)        for(__typeof((s).end()) i=(s).begin(); i != (s).end(); i++)



/**-------Upper & Lower Bound-------*/

#define LB(a, v)            (lower_bound(all(a), v))

#define UB(a, v)            (upper_bound(all(a), v))



/**--------DeBug------------*/

#define watch(x)            cout<<(#x)<<" is "<<x<<"\n"

#define chk                 cout<<"Wtf"<<"\n"



const int mod = 1e9 + 7;

const int mx  = 2*mx5;



int main(){

    ll x; sfl(x);

    if(x<=6){pfl(1); return 0;}

    ll ans = 2*(x/11);

    ll rem = (x%11);

    if(rem == 0);

    else if(rem <= 6) ans++;

    else ans+=2;

    pfl(ans);



    return 0;

}