#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <queue>
#include <cmath>
#include <climits>
#include <iomanip>
#include <set>
#include <map>
using namespace std;
typedef long long ll;
int main(){
  ll n;
  cin >> n;
  cout << n / 3 << endl;
}
#include <bits/stdc++.h>
#define _GLIBCXX_DEBUG
#define rep(i,n) for(int i=0;i<(n);++i)
#define repi(i,a,b) for(int i=int(a);i<int(b);++i)
#define all(x) (x).begin(), (x).end()
#define PI 3.14159265358979323846264338327950L
using namespace std;
typedef long long ll;
typedef long double ld;
int main() {
    string s,t;
    cin>>s>>t;
    cout<<t<<s;
}