/**
 *  written by Binoy Barman .
**/

#include<bits/stdc++.h>
using namespace std;
#define nl '\n'
#define all(v) v.begin(), v.end()
#define Too_Many_Jobs int tts, tc = 1; cin >> tts; hell: while(tts--)
#define Dark_Lord_Binoy ios_base::sync_with_stdio(false); cin.tie(NULL);

#ifdef LOCAL
#include "debug/whereisit.hpp"
#else
#define dbg(...) 42
#endif
#define int long long

int32_t main() {
Dark_Lord_Binoy
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    int n;
    cin >> n;
    if(n == 2 || n == 3) {
        cout << 1 << nl;
    } else {
        int ans = n / 3;
        int l = n % 3;
        if(l) ans++;
        cout << ans << nl;
    } 


    return 0;
}