#include "bits/stdc++.h"
using namespace std;
#define print(x) cout<<x<<endl;
#define rep(i,a,b) for(int i=a;i<b;i++)
#define REP(i,a) for(int i=0;i<a;i++)
typedef long long ll;
typedef pair<int, int> PI;
typedef pair<int, PI> V;
typedef vector<int> VE;
const ll mod = 100000000000;

using namespace std;

int main() {
  ll n;
  cin>>n;
  ll ans=0;
  ans+=n/3*2;
  ans+=n/5*2;
  cout<<ans<<endl;
}