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

#define ll long long
#define vc vector<int> 
#define pr pair<int,int>
#define PB push_back
#define MP make_pair
#define loop(i,a,b) for(int i = a; i<= b; i++)
#define YES cout<<"YES"<<endl;
#define NO cout<<"NO"<<endl;
#define bb begin()
#define ee end()
#define ff first
#define ss second
#define fastio ios::sync_with_stdio(false);cin.tie(NULL);

void solve();

int main()
{
    fastio
    int t;t=1;
    while(t--) solve();
    return 0;
}

void solve(){
    int n;cin>>n;
    if(n%3==0) cout<<n/3<<endl;
    else cout<<n/3+1<<endl;
}