#include<iostream>
#include<string>
#include<algorithm>
#include<cctype>
#include<set>
#include<bitset>
#include<math.h>
#include<map>
#include<queue>
#include<iomanip>
using namespace std;

int main(){
    long long n, sum1 = 0;
    cin >> n;
    sum1 += n/3*2;
    sum1 += n/5*2;
    cout << sum1 << endl;
}