#include <iostream>
#include "math.h"
using namespace std;

int main() {
    // insert code here...
    long long n;
    long long threeNum,fiveNum;
    
    cin >> n;
    threeNum = n/3;
    fiveNum = n/5;
    
    long long ans = 2 * (threeNum + fiveNum);
    
    cout << ans <<endl;
    

    return 0;
}