#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define pb push_back
#define fast ios::sync_with_stdio(false);cin.tie(nullptr)

 int gcd(int a, int b) {
     if(b == 0) {
         return a;
     }
     else {
         return gcd (b, a%b);
     }
 }

 ll lcm(ll a, ll b) {
     return a / gcd(a, b) * b;
 }

 string toupper(string a) {
     for (int i = 0; i < (int)a.size(); ++i)
         if (a[i] >= 'a' && a[i] <= 'z')
             a[i] -= 32;
     return a;
 }

 string tolower(string a) {
     for (int i = 0; i < (int)a.size(); ++i)
         if (a[i] >= 'A' && a[i] <= 'Z')
             a[i] += 32;
     return a;
 }

 bool prime(ll a) {
     if (a == 1)
         return false;
     for (int i = 2; i <= round(sqrt(a)); ++i)
         if (a % i == 0)
             return false;
     return true;
 }

 constexpr long long pow(long long a, long long b) {
     long long res = 1;
     for (; b; b /= 2, a *= a) {
         if (b % 2)
             res *= a;
     }
     return res;
 }

 constexpr int factorial(int k) {
     int res = 1;
     for (int i = 2; i <= k; i++)
         res *= i;
     return res;
 }

bool check() {
    return true;
}

 bool cmp(pair<int, int> a, pair<int, int> b) {
     if (a.first == b.first) return (a.second > b.second);
     return (a.first < b.first);
 }

 int power_MOD (int base, int p, int m) {
     int res = 1;

     while (p) {
         if (p % 2 == 1) {
             res = (res * base) % m;
             p--;
         }
         else {
             base = (base * base) % m;
             p = p / 2;
         }
     }
     return res % m;
 }

 //** Bitwise --> begin

 // swap ( x, y ) --> x=x^y, y=x^y, x=x^y
 // if x=a then x=b // if x=b then x=a --> x=a^b^x
 // a+b=(a^b)+2(a&b)
 // a+b=(a|b)+(a&b)

 bool check_odd ( ll x ) {
     return (x & 1); // odd ecen check
 }
 bool check_kth_bit ( ll x, ll k ) {
     return (x & (1LL<<k));  // k'th bit set or not
 }
 ll set_kth_bit_1 ( ll x, ll k ) {
     return (x | (1LL<<k));   // make k'th bit 1;
 }
 ll set_kth_bit_0 ( ll x, ll k ) {
     return (x & ~(1LL<<k));   // make k'th bit 0;
 }
 ll mul_num_by_2_pow_k ( ll x, ll k ) {
     return (x<<k);   // x*(pow(2,k))
 }
 ll dic_num_by_2_pow_k ( ll x, ll k ) {
     return (x>>k);   // x/pow(2,k)
 }
 int set_bit_count_int ( int x ) {
     return __builtin_popcount(x);  // int set bit count
 }
 ll set_bit_count_ll ( ll x ) {
     return __builtin_popcountll(x); // ll set bit count
 }
 ll toggle_kth_bit ( ll x, ll k ){ // if k = 0 then k = 1
     return (x ^ ( 1LL <<k ));  // if k = 1 then k = 0
 }
 bool power_of_2 ( ll x ) {
     return (!(x&(x-1))); // power of 2 checking
 }

//** Bitwise --> endl

void solve() {
    int x;
    cin >> x;
    int fk = x;
    int c1 =0 , c2 = 0;
    while (fk) {
        c1++;
        fk -= 3;
    }
    if (fk) cout << c1+1 << endl;
    else cout << c1 << endl;
}

int main() {
    fast;
	int tc;
  //  cin >> tc;

  //  while (tc--) {
        solve();
   // }

    return 0;
}