#include <iostream>
#include <string>
#include <vector>

#define rep(i,n) for (int i = 0; i < (n); ++i)

using std::cin;
using std::cout;
using std::endl;
using std::string;
using std::vector;

int main() {
  long long x;
  cin >> x;

  long long count = (x / (5 + 6)) * 2;
  if (x % (5 + 6) == 0) {}
  else if (x % (5 + 6) <= 6) count++;
  else count += 2;

  cout << count << endl;

  return 0;
}
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> VI;
typedef vector<vector<int>> VVI;
typedef vector<ll> VLL;
typedef vector<vector<ll>> VVLL;
typedef pair<ll, ll> Pair;
template <class T> T input() {T t; cin>>t; return t;}
#define FOR(i,a,b) for (ll i = a; i < b; i++)
#define REP(i,b) FOR(i,0,b)
#define RFOR(i,a,b) for (ll i = a-1; i >= b; i--)
#define RREP(i,a) RFOR(i,a,0)
#define REPALL(i,x) for (ll i = 0; i < x.size(); i++)
#define RREPALL(i,x) for (ll i = x.size()-1; i >= 0; i--)
#define REPITR(itr,x) for (auto itr = (x).begin(); itr != (x).end(); itr++)
#define ALL(x) (x).begin(), (x).end()
#define SORT(x) sort(ALL(x))
#define MIN_ELEMENT(x) min_element(ALL(x))
#define MAX_ELEMENT(x) max_element(ALL(x))
#define COUNT(x,num) count(ALL(x), num)
#define MEMSET(x,val) memset(x, val, sizeof(x))
#define CHMAX(a,b) a = max(a,b)
#define CHMIN(a,b) a = min(a,b)
#define FIND(x,key) x.find(key) != x.end()
#define IN_RANGE_V2(v,k,x,y) (0<=x+dx[k]&&x+dx[k]<v[y].size()&&0<=y+dy[k]&&y+dy[k]<v.size())
#define debug(x) cerr<<__LINE__<<": "<<(#x)<<" = "<<(x)<<endl;
void YES(bool flag) {cout<<(flag ? "YES" : "NO")<<endl;}
void Yes(bool flag) {cout<<(flag ? "Yes" : "No")<<endl;}
void yes(bool flag) {cout<<(flag ? "yes" : "no")<<endl;}
#define PRINT_ARRAY_H(a) REPALL(__i,a) {cout<<a[__i]<<(__i != a.size()-1 ? " " : "");} newline;
#define PRINT_ARRAY_V(a) REPALL(__i,a) {cout<<a[__i]<<endl;}
#define e1 first
#define e2 second
#define newline putchar('\n')
#define cspace ' '
#define sspace " "
const int INF = 1e7;
const ll MOD = 1e9 + 7;
const double pi = 3.141592653589793;
const VI dx = {1, 0, -1, 0};
const VI dy = {0, 1, 0, -1};
//const VI dx = {1, 1, 0, -1, -1, -1, 0, 1};
//const VI dy = {0, 1, 1, 1, 0, -1, -1, -1};

void solve()
{
    ll a, b, c, d, n, m, l, r, k, x, y, z, ans = 0ll;
    string s, t;
    cin>>n;
    l = 0, r = n;
    ll mid = (l + r) / 2;;
    string s0;
    cout<<0<<endl;
    cin>>s0;
    if (s0 == "Vacant") {
        return;
    }

    while (true) {
        mid = (l + r) / 2;
        cout<<mid<<endl;
        cin>>s;
        
        if (s == "Vacant") {
            break;
        } else if (s == s0) {
            if (l % 2 == mid % 2) {
                l = mid;
                s0 = s;
            } else {
                r = mid;
            }
        } else {
            if (l % 2 == mid % 2) {
                r = mid;
            } else {
                l = mid;
                s0 = s;
            }
        }
    }
}

int main()
{
    cout<<fixed<<setprecision(20);
    int __t = 1;
    //cin>>__t;
    REP(i,__t) {
        solve();
    }
    return 0;
}