#define _USE_MATH_DEFINES
#include<stdio.h>
#include<string>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include<iomanip>
//#include<bits/stdc++.h>


using namespace std;

int main(){


	long long int b,a=0;
	cin>>b;
	a+=b/3;
	a+=b/5;
	cout<<a*2<<endl;
	

	
	return 0;
}