#include<bits/stdc++.h>
using namespace std;
#define ll long long
void solve(){
    int n;
    cin >> n;
    int cnt = 0;
    while(n > 0){
        if(n % 3 == 0){
            n-= 3;
        }
        else {
            n -= 2;
        }
        cnt++;
    }
    cout << cnt << '\n';
}
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t = 1;
    //cin >> t;
    while(t--){
        solve();
    }
    return 0;
}