#include <iostream>
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
void solve(){
    ll n;   cin>>n;
    int op = 0;
    while(n>0){
        n-=3;
        op++;
    }
    cout<<op<<endl;
}


int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);
    int t=1;  //cin>>t;
    while(t--){
        solve();
    }
    return 0;
}