#include <bits/stdc++.h>
using namespace std;
#define REP(i,N) for(int i=1;i<=N;i++)
int main() {
	long long int N,san,go,sum;
	cin>>N;
	san=N/3;
	go =N/5;
	sum = (san+go)*2;
	cout<<sum<<endl;
	return 0;
}