#include <iostream>
#include <iomanip>
#include <vector>
#include <set>
#include <string>
#include <queue>
#include <algorithm>
#include <map>
#include <cmath>
#include <numeric>
#include <list>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <tuple>

#define rep(i, n) for (int i = 0; i < (n); i++)
#define rep1(i, n) for (int i = 1; i <= (n); i++)
#define show(a, n) rep(i,n) {cout<<a[i]<<' ';} cout<<endl
#define show2(a, n, m) rep(i, n) { rep(j, m) {cout << a[i][j] << ' ';} cout << endl;} 
#define chmin(a, b) a = min(a, b)
#define chmax(a, b) a = max(a, b)

using namespace std;
typedef vector<int> vi;
typedef pair<int, int> pii;
typedef long long ll;
typedef vector<ll> vll;
typedef pair<long long, long long> pll;
typedef long double ld;

const int INF = 1 << 30;
const long long INFL = 1LL << 60;
const int MOD = 1000000007;
const int MAX = 100000;
const int N = 100010;

int main() {
//	cout << fixed << setprecision(15);
	int n;
	cin >> n;
	cout << n / 3 << endl;
}

#include <bits/stdc++.h>
using namespace std;
#include <math.h>
#include <iomanip>
const int INF=1001001001;

int main() {
  int64_t N;
  cin>>N;
  int x=N;
  string t;
  while(x){
   int r=x%(-2);
   if(r<0){r+=2;}
   x-=r;
   x/=(-2);
   t+=(char)('0'+r);
  }
  reverse(t.begin(),t.end());
  if(t==""){t='0';}
  cout<<t<<endl;
  return 0;
}